miss fireing
 

hi,ive got a 93 wrx import,i have a problem with it miss fireing under hard acceleration mainly in first and second gear and it does not seem to want to pull when this happens,it doesnt do it all the time but it does it when it is hot or cold,i have done a diagnostic test on it and its not showing anyfaults,have had the plugs changed (pfr7b) about 2 weeks ago it started after about 1 week of the plugs being in,any one got any ideas on what it could be?

Mate, I had the same feckin problem with a MY99 WRX in Australia about a year an a half ago. Same thing as you described and I had bought it from a Subaru garage. They never did find out what it was despite several inspections and diagnostics.

Sorry, but will be interesting to see what peoples responses to this is.

Very likely to be the coilpacks if the problem has occurred after changing the plugs. When the coilpacks are removed they can crack around the tips (under the rubber shrounds) when disturbed - this will cause hesitation/miss-firing especially under boost ;)

Cheers

ok thanks have to try a new set

got a new set of coil packs £225 incvat and it fixed the problem my old coil packs had all cracks in them around by the rubber seal well 3 out the four were well nakerd QUOTE=neil5536]ok thanks have to try a new set[/QUOTE]