Anyone ever dropped a single cylinder periodically ? Swapped coil pack but misfire is always No 4. Wiggled wiring, but makes no difference.

 

Comes & goes, but usually clears up after a bit of driving - is this the first sign of the dreaded PTU failure ??

It might be, but it is slightly more likely that it's an injector connector problem.

Did wonder about that, but when it's off there's no spark from the coil pack, so must be ignition.

could be corroded connectors on the PTU or check if the connector on coilpack of #4 is damaged of some sort.

 

-Eric

Yeah I had cylinder 5 going intermittantly when my PTU went. Would be fine for a while, then suddenly would drop a cylinder for 5 minutes or so. I took the PTU off (5 minute job) and did the continuity test described in the service manual with a multimeter. It showed that pin 5 was not always working (the test worked about 5 times and failed twice)

 

 

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Could it be the injector as that would loose the cylinder despite the swapping of coils?

Just a thought

Mark

Cheers guys, I'll check the PTU connectors next time I see the car - its in scotland and I'm in birmingham at the moment