FAQ
TL;DR: Cold-start jerking with “Antipollution fault” on Peugeot 307 often traces to the ignition coil. One tech logged 3 cases; "there is no need to wonder"—install a quality new coil, not the cheapest. [Elektroda, Frost160, post #16730755]
Why it matters: This FAQ helps 307 owners quickly diagnose cold-start misfire and choose effective, budget-smart fixes.
- Symptom pattern: jerks on cold start, fault lamp, then smooth after warm-up; LPG runs fine when hot. [Elektroda, Paulina95t, post #16730526]
- Priority: "Accurate diagnostics and reading errors and parameters" before swapping parts. [Elektroda, spinacz, post #16730366]
- Coils: Sagem units commonly fail; Meyle praised; avoid the cheapest replacements. [Elektroda, Frost160, post #16730755]
- Moisture can cause HV tracking; warm-up dries it, masking misfire. [Elektroda, robokop, post #16731339]
- Reported compression 13.5–13.8 bar across cylinders suggests ignition, not mechanical damage. [Elektroda, Paulina95t, post #16730343]
Quick Facts
- Symptom pattern: jerks on cold start, fault lamp, then smooth after warm-up; LPG runs fine when hot. [Elektroda, Paulina95t, post #16730526]
- Priority: "Accurate diagnostics and reading errors and parameters" before swapping parts. [Elektroda, spinacz, post #16730366]
- Coils: Sagem units commonly fail; Meyle praised; avoid the cheapest replacements. [Elektroda, Frost160, post #16730755]
- Moisture can cause HV tracking; warm-up dries it, masking misfire. [Elektroda, robokop, post #16731339]
- Reported compression 13.5–13.8 bar across cylinders suggests ignition, not mechanical damage. [Elektroda, Paulina95t, post #16730343]
What does “Antipollution fault” usually indicate on a 307 with cold-start jerking?
It usually accompanies a misfire that raises emissions. Start with a scan, then verify live parameters before parts swapping. “Accurate diagnostics and reading errors and parameters” keeps costs down and fixes on target. [Elektroda, spinacz, post #16730366]
Why does it jerk only when cold but smooth out when warm?
Cold, damp conditions can let high-voltage leads or coil packs track to ground. As the engine bay warms and dries, the misfire fades. That creates a misleading “fixed when hot” pattern, even though the root cause remains. [Elektroda, robokop, post #16731339]
Will a new ignition coil actually fix this fault?
Often yes, if the coil is failing. “First, replace the coil with a new one,” then recheck codes and operation. Use a reputable brand rather than the cheapest option to avoid repeated faults. [Elektroda, robokop, post #16730723]
Are used coils or the cheapest new coils a false economy?
Yes. Members report repeat failures with bargain coils. One technician installed Meyle with solid results and warned against the cheapest options. Used coils carry unknown wear and hidden defects. [Elektroda, Frost160, post #16730755]
My mechanic mentioned hydraulic tappets (pusher glasses). Could they cause jerking here?
Given the cold-only misfire and warm-up recovery, focus on ignition first. Chasing tappets and timing adds cost and distraction. Address the coil and HV tracking before deeper mechanical work. [Elektroda, robokop, post #16731339]
Should I change oil viscosity to stop the misfire or the fault message?
No. The thread points back to ignition components and stored codes, not oil weight. Confirm a quality new coil and read the controller’s exact error before considering unrelated work. [Elektroda, robokop, post #16740752]
Do my compression numbers point to engine damage?
Reported compression of 13.5–13.8 bar across cylinders is even. That level supports good mechanical condition. It shifts suspicion to ignition, wiring, or HV tracking instead of valves or rings. [Elektroda, Paulina95t, post #16730343]
How should I diagnose this before buying more parts?
Follow three steps:
- Scan and note exact fault codes and freeze-frame data.
- Inspect coil and HV boots for carbon tracking or moisture marks.
- Test with a known-good coil and fresh plugs, then rescan.
“Accurate diagnostics” saves money. [Elektroda, spinacz, post #16730366]
Why does it run well on LPG and petrol once warm?
Warm-up reduces condensation and moisture, improving insulation around HV components. Any cracked boots or marginal coils behave better when dry. The underlying ignition fault can still return with cold, damp starts. [Elektroda, robokop, post #16731339]
Which replacement coil brands were recommended in this case?
Valeo was installed, and Meyle was recommended for durability and fair price. The contributor also highlighted recurring issues with Sagem coils and warned against the cheapest units. [Elektroda, Frost160, post #16730755]
What information from the scan tool is most important to record?
Capture the precise error signature stored in the controller. Note cylinder-specific misfire counts and conditions when the fault set. This targets testing and confirms the fix after parts replacement. [Elektroda, robokop, post #16740752]
The fault disappeared then came back—what does that suggest?
That pattern fits intermittent HV tracking or moisture effects. Heat temporarily dries components, but the underlying leakage or crack remains. Address coil integrity and boots, then verify with a rescan. [Elektroda, robokop, post #16731339]
