SORTING RULES - IGNITION COIL COMPLAINTS (P0351 IGNITION COIL A PRIMARY/SECONDARY CIRCUIT, P0352 COIL B, AND P0353-P0358 FOR COILS C TO H)
PulsCar analysis of NHTSA public data, October 2026. License: CC BY 4.0

Fingerprint of the rules text below, taken when it was written and before any complaint was sorted: 56c7ed0ac99d44a1ce216463516f92b20d3b50f6f381cae235162c9dbf75b3cb (2026-10-30T16:14:32Z)

[Changed when published, wording only: the title line moved up; one reference to a file of search expressions replaced by "written out in the pool history at the end of this file"; one sentence about passing narratives on for sorting reworded. No rule changed.]

Written before any complaint in the set was sorted.

## Pool (how the complaints were found)
NHTSA complaints received 2015-01-01 to 2026-10-04 (the latest received date in the flat files). A complaint is in the pool if its narrative
matches any of the following case-insensitive text searches (the exact expressions are written out in the pool history at the end of this file):

1. R1 - the code P0351 to P0358 by any spelling (letter O for zero, a space, hyphen or period after the P, suffix 00), or a bare number after a
   code word (code, codes, dtc, error, cel, coded, fault):
   `(?<![A-Z0-9])P\s?[-.]?\s?[0O]\s?3\s?5\s?[1-8](?:\s?[-:]?\s?[0O]{2})?(?![0-9])`
   `\b(?:code|codes|dtc|dtcs|error|cel|coded|fault)\W{0,6}#?\s?[0O]?35[1-8]\b`
2. R2 - the part named as a whole: ignition coil(s), spark coil, coil pack(s), coil-on-plug, coil boot(s), "coil and plug(s)", "plug(s) and coil(s)".
3. R3 - the bare word "coil" or "coils" with a misfire word (misfire, miss fire) or the word cylinder or a P0xxx code within 70 characters,
   unless the 25 characters around "coil" show another meaning (spring, coil-over, air conditioning, A/C, evaporator, heater, condenser, battery,
   starter, alternator, fan, radiator, suspension, strut, shock, windshield, window, seat).

Every narrative that matches any search is sorted (from a window around the matching words). Nothing is sampled.

Background for the reader (not a sorting rule): P0351 is the code for "ignition coil A primary/secondary circuit", P0352 for coil B, and P0353 to
P0358 continue the series for coils C to H. The engine computer switches each coil on and off and watches the circuit; the code says the circuit
(power, ground, wiring, the coil itself, or the computer's driver) did not behave as expected - it does not say which part is at fault.
Owners say "coil", "coil pack", "misfire", "bucking", "runs rough", "check engine light flashing", "cylinder 3 misfire", "spark plug", "boot", "plug well full of oil".

For each complaint record exactly one CATEGORY and five yes/no FLAGS. You see an excerpt around the matching words (and the whole narrative
when nothing matched). Code what the excerpt supports; if it is cut off at a point that matters, code what is stated.

## RELEVANCE
N - Not an ignition-coil / ignition-circuit event on THIS vehicle. Use N when:
    - the match is false (the words appear in another meaning: coil spring, A/C coil, headlight, wire coil, a different part named "coil");
    - "coil" or the part is only named in a list of parts, or in a general sentence, and the narrative does not say that a coil, coil boot, coil circuit or
      ignition spark fault was found, suspected by a shop, replaced, or is the subject of a recall/TSB for this vehicle's engine problem;
    - the words come from another vehicle, a news story or general advice, not this vehicle;
    - the complaint is about something unrelated to the engine running (brakes, airbag, transmission only) and the coil word is incidental.
  NOT N (relevant) when, on this vehicle: P0351-P0358 is named; OR a coil / coil pack / coil boot / coil connector / ignition coil circuit is named by a
  shop, dealer, mechanic, code reader or the owner as the cause or suspect of a misfire, rough running, stall, loss of power, no-start or warning light, or was
  replaced for it; OR a recall, TSB or campaign about ignition coils (or their wiring/ground) is stated as performed, offered, missing or asked about.

## CATEGORY (one letter) - what was found or done, on this vehicle

C - Ignition coil itself. One or more coils / coil packs / coil-on-plug units were named by a shop, dealer or mechanic as the cause, or were replaced
    for this fault, with no deeper cause stated (including "coils and plugs replaced together" when no single cause is named).
P - Spark plug(s). Spark plugs (worn, fouled, wrong gap, cracked, wrong type, loose) were named as the cause or replaced first and no coil fault is named.
    If the plugs are named as the cause of the coil failure (for example worn plugs overloading the coils), use P.
L - Leak or contamination at the coil. Oil in the spark plug wells, oil-soaked coil or boot, coolant or water on the coil or in the well, a leaking valve cover
    or plug-tube seal was named as the cause of the coil/plug misfire (even if the coils were replaced too).
W - Circuit. A wiring harness, connector, pin, ground, fuse, relay, power supply to the coil, ignition module or the engine computer's ignition driver
    was named as the cause or replaced. (The circuit that feeds and fires the coil, not the coil itself.)
I - Fuel injector or fuel delivery named as the cause or was the repair (injector, fuel pressure, fuel pump, contaminated fuel).
A - Air, vacuum, intake or sensor named as the cause or repair (vacuum leak, throttle body, MAF/MAP, crankshaft/camshaft sensor, PCV, EVAP).
M - Engine mechanical. Valves, compression loss, camshaft/lifter/rocker, timing chain or phaser, piston, cracked head, head gasket, oil burning or oil
    consumption destroying coils/plugs, a failed engine or an engine replaced/rebuilt was named as the cause or repair.
F - Software or campaign only. A reflash / software update / relearn, TSB, special-coverage or recall procedure was the only repair stated (no part
    named as cause) - including a recall remedy that replaces coils is C only if the owner says coils were replaced; a recall for coil wiring/ground is W.
O - Another cause. A repair outside the categories above (transmission, turbo, exhaust, battery, alternator, other system) was named, or the fault
    was traced elsewhere.
K - Checked and cleared. The shop or dealer inspected or tested and found no fault, or only cleared the code, with no repair; or the problem went away
    by itself and nothing was done.
U - No diagnosis or repair stated. The event is reported but nothing was found or done yet, or the complaint does not say; also an owner's own guess,
    a code reader or scan with no shop/dealer/mechanic mentioned.

Precedence when more than one fits:
1. Use the FINAL repair the complaint reports as having fixed the problem (or, if it never got fixed, the cause the shop or dealer named last). A part
   replaced that the owner says did not help does not count.
2. If a coil was replaced AND a cause behind the coil was named by a shop (leak/oil in the well L, wiring/connector W, worn plugs P, engine oil burning M),
   the cause behind the coil wins.
3. Several parts replaced together and no cause named: use the most specific named part in the order C, P, W, I, A, M.
4. Among F, O, K, U: F before O before K before U.
5. A cause the owner merely guesses at does not count (an owner's "probably the coil" is U unless a shop, the dealer or a code reader said it, or the part
   was replaced by someone).
6. When the narrative shows the coil was replaced and the fault "came back" with no later cause stated, the category stays C and the flag returned = yes.

## FLAGS (yes/no)

stall - the complaint states that while driving or at a stop the engine stalled, shut off, lost power, bucked badly or went into limp/reduced power
    because of this fault (not a failure to start).
flash - the complaint states that the check engine light FLASHED (blinked) or the owner describes a flashing warning light with this fault.
recall - the complaint states that a recall, special coverage, service campaign, extension, TSB or "known issue" notice for this vehicle was performed,
    offered, missing, refused, asked about, or is blamed or credited for this event.
returned - the complaint states that after a repair or a reset the same light, code or symptom came back, that the part failed again, or that the repair
    did not fix it.
burn - the complaint states smoke, burning smell, a melted/burnt/cracked coil or boot, arcing/sparking, or an engine-compartment fire tied to this fault.

## OUTPUT

One CSV line per complaint, in the order given, no header line:
`odino,category,stall,flash,recall,returned,burn,note`
category is one letter (N C P L W I A M F O K U); flags are yes or no (for N, all five flags are no);
note is at most 15 words, no commas, saying what decided the category.

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RULES USED TO SETTLE DISAGREEMENTS (each decision in the published complaints file names the rule applied in the column rule_applied; the letters after the number - a, b, c, d - mark the group of complaints the rule was written for; the numbers R1 to R3 of the pool searches above are a different list)
- R1 Parts replaced together (plugs + coils, or coils + other parts) with no single cause named: category C if a coil was replaced for a misfire/ignition fault.
- R2 A replacement that the narrative says did not fix it, followed by a deeper cause named by a shop/dealer/mechanic (engine oil burning, coolant leak into a cylinder, valve/head/internal damage, injector, computer): the deeper cause wins (M, I, W, O as fits). If no later cause is named, the category stays C and returned=yes.
- R3 Codes or the light coming back after coils (or plugs+coils) were replaced, no later cause named: category C (or P if only plugs were replaced), returned=yes.
- R4 returned=yes only when the SAME fault (same code, same symptom, same part) comes back after a stated repair or reset, or the repair is said not to have fixed it. A different, later problem (for example a clogged converter found later) is returned=no.
- R5 recall=yes when a recall, TSB, service campaign, special coverage, warranty extension or "recall" notice is named as performed, offered, missing, refused, or asked about ("why no recall?"). An owner's opinion "known defect / known problem" or a mention of a lawsuit/class action alone is recall=no.
- R6 stall=yes when the engine stalled, died, shut off, lost power, went into limp mode, or the car would not accelerate / bucked so that the driver lost power while driving. Shaking alone, hesitation alone, or a failure to start is stall=no.
- R7 C needs the coil named as cause, or replaced for this fault, by a shop/dealer/mechanic/code reader. An owner's own guess without a shop/replacement is U. "Per diagnosis" or "the dealer said it needs a coil" is C.
- R8 N when the coil is only mentioned in a list, a general wish or a different vehicle, and the narrative states no coil/ignition fault for this vehicle.
- R9 Plugs replaced first, coil not named at all: P. Coil named in the same sentence as the cause: C.
- R10 When the excerpt does not settle a field, choose the narrower reading (flag no; category U) and note the doubt.
- R11a A plug (with or without its coil) seen ejected/blown out of the head, no shop diagnosis needed: category P (plug named as cause of the coil damage, even if the engine was damaged after); a heli-coil or plug ejection with no ignition coil named is N.
- R12a After a stated repair, a further failure of the same part type (another coil on another cylinder) = returned yes; failures with no stated repair between = returned no.
- R13a Loses speed / will not accelerate / bogs down / speed drops with pedal pressed = loss of power, stall yes (R6).
- R14a A demand or wish for a recall or warranty extension (needs a recall, should be recalled, why no recall) = recall yes; "known issue/problem" opinion alone stays no (R5).
- R15a "Repaired numerous/several times" for the same fault = returned yes.
- R16a A near-fire or "could have caught fire" = burn no; actual smoke, burning smell, flame, melted part, arcing in the stated event = burn yes.
- R17a Coil replaced and a ground strap/wiring added per bulletin for the same fault = W (cause behind the coil).
- R18a "Burned out / fried / burnt out" meaning electrically failed is not burn; burn needs smoke, smell, visibly melted or burnt part, flame or arcing.
- R19a A coil replacement named only as a side expense inside a complaint about another system (steering, rust, parts list) with no ignition symptom = N; coil replaced inside the engine complaint itself is not N.
- R20a PCM/ECM named together with coil codes (P0351-P0356) or "computer not reading the coil" as cause behind the coil = W.
- R21a flash=yes only when the check engine / misfire light itself flashes; flashing dash or coolant lights = no.
- R22a PCM/ECM or a mount/other part named as cause with no link to ignition driver or coil firing = O.
- R11b Spark plug (and coil) ejected or blown out of the head: the plug-thread failure is the cause, category P (coil is collateral); if heads or engine replacement is the final repair named, category M.
- R12b recall=yes when the narrative states or asks about this vehicle's recall status (no recall, why no recall, VIN not covered, dealer/maker says none, TSB/CSP/campaign named); a bare demand (should/needs/please recall), "known problem", lawsuit or class action alone = no.
- R13b Coil or coil pack replaced (by anyone) for an engine running symptom (misfire, stall, rough, shutoff, power loss) among other parts with no shop-named cause: category C by sorting rules precedence 3, never U.
- R14b A cause only the owner guesses or asserts (oil burning, coolant, head gasket, fuel pump) does not displace C; an owner saying "coil failed" with no shop, reader or replacement stays U.
- R15b N when the coil is only pulled to inspect a cylinder, or sits in a long parts list for a non-ignition symptom (no-crank, turbo), or belongs to another vehicle; all flags no.
- R16b stall=yes when the engine died, lost power, failed to accelerate, bogged, would not stay running or went to limp mode while driving; no for "almost stalled", "can stall", hesitation, shaking, no-start, or a later separate problem.
- R17b returned=yes only when the narrative states persistence or recurrence after a stated repair or reset (still misfiring, code came back, parts re-replaced); a later different problem (overheating, coolant loss, engine failure) or a diagnostic swap with no repair = no.
- R18b burn=yes for a melted or burnt coil, fire, smoke or burning smell concurrent with the misfire event; smoke or odor that appears only in a later overheating or coolant phase = no.
- R19b A deeper cause named by a shop behind the coil wins (R2): oil leak at plugs or coils = L; head gasket, heads, block, compression, engine replacement, oil consumption linked by the shop = M.
- R11c Coil/plug only pulled, inspected, tested or swapped as a diagnostic step (or ruled out by owner/shop) with the problem attributed elsewhere and nothing replaced: N, all flags no. Coil named only as a neighbour/location (stained, rubbed, wiring routing) with no ignition fault: N.
- R12c Computer/PCM/CPU named as cause with no explicit link to the ignition driver or coil circuit: O (W only with an explicit link).
- R13c Coil/plug replaced by anyone as an attempted fix for the complaint's engine symptom, no shop-named cause: C (P if only plugs). A cause asserted only by the owner, or engine failures in a long list of repairs not linked to the coil by a shop, do not displace it; a deeper cause named by a shop/dealer does (R2).
- R14c returned=yes only when persistence is stated or plainly shown after a repair; explicit recurring wording (constantly, often, burns through, N times) about the same part counts. A fix that held, a later different problem, or a later diagnosis with no stated continuation = no.
- R15c recall=yes only when a recall/TSB/campaign/CSP/warranty extension for this vehicle is stated performed, offered, refused, missing, not covered, or asked about as "why no recall"; bare demand (needs/should be recalled), "known defect", "Ford knew", lawsuit or class action = no.
- R16c stall=yes for engine died, lost power, would not accelerate, limp/reduced power while driving; no for shaking or rough alone, "almost/could stall", future-risk wording, or an earlier separate solved problem.
- R17c flash=yes only when the check-engine/misfire light blinks; generic flashing dash warnings = no.
- R18c burn=yes only for smoke/burning smell/melted part stated inside the fault event itself, not in a list of unrelated failures.
- R19c Spark plug ejected from the head: P (plug named as cause), unless head or engine replacement is the final repair named.
- R20c A suspect named last by a shop/dealer ("likely injector", "fuel relay fuse") counts under precedence 1; where two shop-named causes tie, the order C,P,W,I,A,M breaks the tie.
- R11d A statement that no recall/TSB exists, was issued, covers this VIN or was refused, about this vehicle's engine/ignition problem, states recall status: recall=yes. A bare demand (should/needs/please recall) with nothing more = no.
- R13d A coil/plug/part described as burnt or melted (physical state) = burn yes; "burned out", "fried", "burnt up the module", "cracked", "carbon buildup" = burn no. A cracked coil alone is not burn.
- R14d The recall/TSB named must concern the ignition/engine/power fault; an unrelated recall (airbag/Takata, brakes, gear, fuel pump on a visit, other models) = recall no.
- R15d Intermittent recurrence of a symptom with no stated repair or code reset (a key-off restart is not a reset) = returned no.
- Note on R14a: it counted a bare demand for a recall as a recall mark, the other groups did not; the final check (Rcons1 below) applied the stricter reading, so a bare demand is recall = no.

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RULES OF THE FINAL CHECK (the resolution column says "changed in consistency pass" for the 97 complaints it changed). Long narratives, and complaints whose recall mark disagreed with recall wording in the text, were re-read in full and judged again by the written rules above and the four decisions below.
- Rcons1 A recall mark is yes only when a recall, technical service bulletin, campaign, warranty extension or special coverage is named, or the narrative states or asks about this vehicle's recall status ("no recall exists", "my VIN is not covered", "why is there no recall"); a bare demand without status ("it should be recalled"), "known problem", a lawsuit or a class action alone is no. This replaces R14a, which counted a bare demand as yes.
- Rcons1 A returned mark is yes only when the SAME fault comes back after a stated repair or reset, or the repair is stated not to have fixed it (R4, R17b).
- Rcons1 A burn mark needs smoke, a burning smell, a visibly melted or burnt part, flame or arcing in the fault event itself (R16a, R18a, R13d, R18b, R18c).
- Rcons1 Category, stall and flash are re-judged from the whole text under the sorting rules and R1 to R22a with the same precedence (the last repair that fixed it, or the cause the shop or dealer named last; a part that did not help does not count).

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THE TEXT SEARCHES AS WRITTEN (case-insensitive; the first search is the union of R1, R2 and R3)
R1 (code): (?<![A-Z0-9])P\s?[-.]?\s?[0O]\s?3\s?5\s?[1-8](?:\s?[-:]?\s?[0O]{2})?(?![0-9])
R1 (bare number after a code word): \b(?:code|codes|dtc|dtcs|error|cel|coded|fault)\W{0,6}#?\s?[0O]?35[1-8]\b
R2 (the part named as a whole): (?:ignition[\s-]+coils?|spark[\s-]+coils?|coil[\s-]*packs?|coil[\s-]*on[\s-]*plugs?|coil[\s-]*boots?|coil[\s-]+(?:and|&)[\s-]+(?:spark[\s-]+)?plugs?|plugs?[\s-]+(?:and|&)[\s-]+coils?)
R3 (the bare word coil): \bcoils?\b with a match of the following within 70 characters on either side: (?:mis[\s-]?fir\w*|miss[\s-]?fir\w*|cylinders?|\bP0[0-9]{3}\b) - and not when the 25 characters around "coil" match: (?:spring|coil[\s-]*over|coilover|air[\s-]*condition\w*|a/c|evaporator|heater|condenser|wire[\s-]+coil|coil[\s-]+of|battery|starter|alternator|fan|radiator|suspension|strut|shock|windshield|window|seat)

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POOL HISTORY
- First search: 2,455 complaints, found by the three text searches above (R1 code 23, R2 the part named as a whole 2,121, R3 the bare word coil with a misfire word, a cylinder or a code nearby 326; 15 complaints matched more than one search; 8 matched only R1, 2,106 only R2, 326 only R3). Nothing was sampled: every complaint the searches returned was sorted. They were sorted in 11 groups of about 230.
- Left out on purpose by the first search: the bare word coil with no misfire word, cylinder or code within 70 characters; ignition wires or spark plug wires with no coil named; ignition switch and key complaints.
- Independent check (a separate search of the whole complaint file, run after the first batch was sorted): about 4,400 narratives were found by nine wider wording searches (the bare word coil with no misfire, cylinder or code nearby; odd spellings such as "ign coil", "ignition.coil", "ignitions coils", "igniton", "coli pack", "cols", "coild"; "COP" and "plug boot"; "ignition pack"; "ignition module" or "ignitor" used in the misfire sense; the code spelled in other ways; cylinder-number wording). About 1,500 passages were read against the same relevance rule and 667 complaints were added; almost all say plainly that the coil or coils were replaced or blamed, with the misfire word, cylinder or code more than 70 characters away. The check was not stopped by a limit (it was allowed up to 900 and found 667). All 667 were sorted twice under exactly the same rules (3 groups of about 222). found_by in the complaints file says which search found each complaint ("first search" or "independent check").
- Left out by the independent check: coil springs and suspension coils, air-bag clock springs, A/C and heater coils, relay and solenoid coils, glow-plug coil lights, key-fob "ignition module" complaints, headlight and air-bag igniters, motorcycles; narratives where a coil appears only in a list of replaced parts with no fault stated; owner generalities about coils on other vehicles.
- Final: 3,122 complaints; 3,010 relevant, 112 not relevant. A relevant complaint is one that names, on the owner's vehicle, P0351 to P0358, or an ignition coil, coil pack, coil boot, coil connector or ignition coil circuit as the cause or the suspect of a misfire, rough running, stall, loss of power, no-start or warning light (or replaced for it), or a recall, bulletin or campaign about ignition coils or their wiring as performed, offered, missing or asked about.
- After the settling of disagreements, a final check changed 97 rows under the same rules: long narratives were re-read in full where the first sorting was uncertain, and the mark was changed where the whole text says so (the sorting had seen only a window around the matching words). The resolution column says "changed in consistency pass".