P39 misfire

dannyboy11 · Feb 9, 2011

I've had an intermitent misfire that i'm trying to diagnose. I think its the coil pack. It usually misfires when the engine is cold, but its started to do it at random times even when the engine has warmed up. I have disconnected the MAF, the engine cuts out immediately. I have also changed the plugs and HT leads.
It sounds like the left side has the problem but thats about as close as I can get to isolating the problem so far.
Any other ideas?
Thanks

j the range · Feb 9, 2011

did you let the engine warm up, befor you unpluged the maf senser..

dannyboy11 · Feb 9, 2011

Yea, it was upto its normal temp.

dannyboy11 · Feb 9, 2011

Should have also mentioned, it only mis fires while driving. If left to idle, it is fine.

j the range · Feb 9, 2011

you need to get some body to keep it running when you unplug the senser, then take it for a drive..

dannyboy11 · Feb 9, 2011

ok, i'll try that

Willos · Feb 10, 2011

Could be a head gasket on its way out. Check all the plugs for a rusty deposit. If you find one on 1,2,7,8 then its definite on its way out. Could be your coil packs, but more than likely a lead not pushed on hard on the plug

dannyboy11 · Feb 14, 2011

I've changed one of the coil packs. The misfire has gone but its still running rough. So I'm thinking that there's a problem with the maf. If i keep the revs up and unplug the maf the engine still runs the same. As there's no one here to help me I cant take it for a drive with the maf disconnected. Can I test the maf with a multimeter to make sure that it is the problem?

P39 misfire

dannyboy11

New Member

j the range

New Member

dannyboy11

New Member

dannyboy11

New Member

j the range

New Member

dannyboy11

New Member

Willos

Active Member

dannyboy11

New Member

Similar threads