Question about 2003 Volkswagen Passat
Got an engine light. Engine sounded a little rough during idle but nothing serious. Had codes read at Advance Auto. Showed all cylinders misfiring. I replaced all spark plugs with proper gap. Also bought a new coil pack and put it in all four positions without any change in performance. Absolutely nothing changed after all this. Engine light still on. Still a little rough at idle and seems to be a little less powerful when accelerating. What should I try next?
Posted by Anonymous on
Its not likley to be an injector fault.the air mass meter is far more common.if you unplug it it defaults to a average value and should improve the way it runs if that is the problem.
Posted on May 21, 2009
Swap #5 injector with another one and see if the miss moves .
If the miss moves then the injector is faulty.
If the miss doesn't move do a compression test and get back to me .
Posted on Jul 03, 2009
I have changed a few cylinder heads under warranty for this type of problem. The exhaust valve guides wear, this causes the exhaust valve to seat badly, giving low compression. if one cylinder compresion reading is more than about 50 psi below the others, then this warrants head removal. It is quite a job, due to the fact that the camshft id chain driven. If you are up for it then once the head is removed, poor liquid into the exhaust ports and see if it leaks out through any of the exhaust valves.
Posted on Jul 23, 2009
Coils and plugs are not the only things that can cause misfires. Misfires can be caused by vacuum leaks, low compression, faulty fuel injectors, clogged EGR ports (on vehicles with individual ports for each cylinder), blown head gaskets, burned valves...you can spend a LOT of money on parts by just going in and replacing things without diagnosing WHY the cylinder is misfiring.
Posted on Feb 27, 2011
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