Bad X20XEV missfire.

[5853moore]

Any help on this one :

Im trying to get to the bottom of the BAD missfire on my missis cavalier. Its been there since we bought the car and its slowly got worse. It only does it when its warm and at low revs, under 3k (all other times its fine). If she dips the clutch it goes away.

Ive had the plugs out and wire brushed them and they all look fine and also changed the HT leads and there helped but its still there.

Its a H reg SRI but the previous owner fitted a x20xev.

[ed2]

we have x20xevs

1) is the ecu wired as a normal x20xev and if so are there any codes?

2) carefully take the spark plugs out one by one and compare the colour of each is all the same??

if cylinder 4, or 3, or 3 and 4 area different colours tothe rest, it may be coolant leaking intothe cylinder as the head gasket is starting to go.

3) I keep spare second hand coil packs off vectras (£10) to swap to see if the coil pack is breaking down.

that is just to start, as it could be a number of things

[planetc]

Process of eliminating things I think, swap the ignition components, and the injector, check for any air leaks around the inlet, then start considering the possibility of a head gasket or valve fault.