Dodgy missfire

[jonnyoutram 0]

hi,

 

i have spent a while on the knowledge base but could not find anything.

 

i have a 1995 m reg vr6 storm, when you start the engine from cold the car seems to run fine but as soon as u give the car any throttel, once the revs drop it seems to struggle! it seems like suddenly 2 cylinders are not fireing?? some times it almost stalls, its sounds really roulgh and then eventuall it sorts itself out once the car warms up??

 

whats going on?

 

i have had a new:

coil pack

ht leads

plugs

oil

filters

 

 

i have cleaned out the throttel body and induction pipework

checked for air leaks and changed a few rubber vacume hoses.

 

i thought it could be the isv so i took it off cleaned it, lubed it up and then tested it and it seemed to work fine...

 

i stuck it on vag com and all that showed up was a few funny readings from the lambda probe, my specialist mechanic mate said it should not cause a problem tho.

 

any ideas ppl?? :notworthy: :notworthy: :notworthy:

[iceviolet 0]

I had a bad missfiring problem last week, and before this my car also behaved like yours does, struggling a bit after you give it some. It turned out to be the coil pack on mine. But as you have had a new one, its very unlikely that it is that. The lambda reading should hover around 1.00. I had a few suggestions by other memebers to the cause of it though, The MAF sensor, knackered cat, blue temp sensor???

[jonnyoutram 0]

I had a bad missfiring problem last week, and before this my car also behaved like yours does, struggling a bit after you give it some. It turned out to be the coil pack on mine. But as you have had a new one, its very unlikely that it is that. The lambda reading should hover around 1.00. I had a few suggestions by other memebers to the cause of it though, The MAF sensor, knackered cat, blue temp sensor???

 

is there any way of testing a coil pack?

 

i know about the spraying water thing and looking out for arking but have already checked that and its not split...???

[dr_mat 0]

You can buy spark testers.

[iceviolet 0]

I tried the water thing with mine too, didnt arc and the resin looked fine, no splits or cracks. I think on mine, one of the actual coils inside the unit had gave up the ghost. How recently has it been replaced??

[jonnyoutram 0]

it was replaces about 6 months ago, its weird how it only does it for a bit on start up when cold only once revved!! is it possible that warming it up could make something electrical work better?

[dukest 0]

viewtopic.php?f=1&t=74001

 

no definitive answers here but just to show you its obviously not that uncommon..

[jonnyoutram 0]

its really strange tho, are u all saying that the coil pac could have it running fine one minute then once revved up only when cold it could loose 2 cylinders till warmed up?? wouldn't it be difficult to test with a spark tester if its an intermittent fault?

[was8v 0]

When its missfiring, kill the enigne and pull the plugs that are missing immediatly.

 

I've had a VR that oiled up its 1&6 plugs after a few k miles (I think due to bore wear) causing missfiring. You would see oil on the plugs and nasty deposits in this case.

 

My current VR had a dodgy injector which failed spraying too much fuel which meant the plug didnt fire. You would have a plug covered in fuel and smelling of petrol if this is ths case.

[jonnyoutram 0]

amazing advice i will check! thank u so much!!! :notworthy: