1999 V40 Random Engine missfire

shanegtr · Post by **shanegtr** » 05 Jan 2014, 01:41

Hi all, hopefully someone has a good ideas for me to look into this issue. Recently my V40 started missfiring. No check engine light and missfire seems to occur at random times. Sometimes its running perfectly fine, then its missing at idle, then at light throttle, heavy throttle etc....

Its only just started this while Im a couple of hundred km's from home so havent had a chance to dig into the issue yet - but I dont have a code reader so Im going to have to get one sorted soon i think.

Anyway I've got two potential causes.
1) I degreased and cleaned the engine bay a couple of days before hand - the car had not done much running around before the miss started. However the car has done around over 600km since the miss started (most of it over 200km at a time) so if it was a water problem then I reckon most of it would have evaparated off by now. Still I will remove all the ignition components to clean and reinstall to check (I'll also pull the sparks when I do this to eliminate them as well)

2) Car was recently fuelled up before hand so theres a chance I've got a dud tank of go juice. Its run to just under half a tank and then refuelled and currenty burned through around 20L of petrol and the miss is still there (possibly getting worse, but I'll see). Any ideas on what to check out if it is indeed a batch of shit fuel?

Any other ideas are most welcome.

difflock54 · Post by **difflock54** » 05 Jan 2014, 14:40

Do any of the vacuum hoses or electrical connectios appear disturbed or loose.
Having degreased and cleaned your engine bay something could easily have become dislodged?

shanegtr · Post by **shanegtr** » 05 Jan 2014, 16:21

I've had a quick look over the vacum lines and all appears ok. Nothing seems outta place, but I havent had a real good look over it all yet

shanegtr · Post by **shanegtr** » 06 Jan 2014, 02:05

Looks like the issue was spark plugs. I haven't done them since I've brought this car (I've only done around 17,000km's in this car since I brought it) so no idea when the last time they where changed. Cylinders 1 & 2 plugs where eroded badly, cylinders 3 & 4 looked better, but still eroded and not the best. Coil pack on cal 4 had a small crack and showing signed of arcing, so swapped that one with a spare I had and alls good now.

t4orce · Post by **t4orce** » 07 Jan 2014, 19:30

Good to know the problems are resolved.

shanegtr · Post by **shanegtr** » 10 Jan 2014, 02:28

Even better that it was an easy fix