grdunn123 Posted November 30, 2010 Report Share Posted November 30, 2010 I've had my mechanic looking at trying to sort out a misfire that recently occurred on a trip home from York. Management light started flashing on and off and the car felt horrible. VAGCOM identified a misfire on cylinder 7 and he's replaced the coil ack and plugs so far......when he takes it out on the road from cold it's fine but after 10 mins or so (warm up) the management light clicks back on and the misfire reappears......he's now checking for a blocked injector Any one have any deas what it might be???? Link to comment Share on other sites More sharing options...
cruiser647 Posted December 1, 2010 Report Share Posted December 1, 2010 Might be the amplifier for that bank of cylinders? Link to comment Share on other sites More sharing options...
IT_S8 Posted December 1, 2010 Report Share Posted December 1, 2010 Defo sounds coil pack to me. Very common on many VAG cars. Not sure what year your car is.... the PF < 1999 cars had a pair of coil packs which drive 8 cylinders each. Facelift cars have it all built into the coil, but vagcom has been known to get the cylinder diagnostic wrong on this... I've be tempted to swop coil packs about and see if the problem shifts, it usually does... A bit of divide and conquer and you can normally track it down... Link to comment Share on other sites More sharing options...
grdunn123 Posted December 1, 2010 Author Report Share Posted December 1, 2010 It's a 2002 4.2 QS....my guy has already replaced the coil pack and 6 out of the 8 plugs ( the other 2 were too tight even after loose oil overnight). He reckons that it drove fine for 10 mins or so on a cold start but after a little warm up the engine light clicks on and the misfire returns... you reckon it might be a coil pack from a different cylinder?? Link to comment Share on other sites More sharing options...
ainarssems Posted December 8, 2010 Report Share Posted December 8, 2010 Swap ignition amplifiers to see if fault goes to another cylinder Link to comment Share on other sites More sharing options...
cruiser647 Posted December 8, 2010 Report Share Posted December 8, 2010 You'll still need to replace those 2 plugs. One of them might be cracked, so once warm - it splits a bit, so the spark timing goes awry. No point replacing just 6!!! When was the last time ALL 8 were changed? Link to comment Share on other sites More sharing options...
matt5791 Posted December 16, 2010 Report Share Posted December 16, 2010 (edited) I had a misfire suddenly come on about a year ago with my old D2 3.7 - out of the blue. I immediately suspected it was ignition related - spark plugs, coils etc. I nursed it from Inverary in Argyll all the way to Perth Audi. They examined the car for about an hour and then came through with a print out showing 18 faults within the fuel system - they deleted them, refused to charge me anything at all (because they said they weren't convinced this was a proper job) but the car remained absolutely fine and never missed a beat until the day I part exchanged it for the D3 3 months later. Lucky - but illustrated to me that what seemed like a very obvious ignition fault was infact something else, so be warned! But, as mentioned above, definitely change those two plugs, even if it is difficult! Edited December 16, 2010 by matt5791 Link to comment Share on other sites More sharing options...
Tatlow Posted December 25, 2010 Report Share Posted December 25, 2010 Hi, Just noticed your thread from recently. You might have had it sorted out by now, but I recently had a similar problem. It started drinking petrol even more than normal and the acceleration came in fits and starts. After checking plugs and coil packs, etc, it turned out to be a defective airflow meter and, now fixed, the old girl is going like a train again now. Link to comment Share on other sites More sharing options...
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