98 Audi A4 misfires.

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  #1  
Old 12-24-08, 11:57 AM
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98 Audi A4 misfires.

The car is a 98.5 Audi A4 2.8L V6. Well a couple months back my car started missing real bad, mainly in cylinder 4. I replaced the spark plugs,the spark plug wires, and the Ignition Coil Pack. None of those fixed my problem so I got frustrated and brought it to the mechanic.
The mechanic first suggested the intake gasket, But he replaced that and it wasn't the problem. So he tried swapping injectors, swapping spark plugs and plug wires, pressure tested the cylinders and all that. Nothing fixed the problem or moved the problem from cylinder 4 and the pressure tests came back perfect. He ordered a scanner from Audi that should be here sometime so he can do more detective work, But he has been waiting for it for a while now.
 
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Old 12-25-08, 06:33 AM
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Shade tree mechanic here.....never worked on an Audi but an engine is an engine is an engine.....

Compression tests are good = gaskets, rings and valves are good.

Changed injectors, no change = injector good
Changed plugs and wires, no change = plugs and wires good

My next "guess" would be to look at the coil pack.

It would seem mechanic would be able to place vehicle on a scanner and look at the spark for each cylinder???? This would give him an idea of what type of waveform and amplitude of voltage is actually be delivered to each one.
 
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Old 12-25-08, 08:25 AM
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I've replaced the coil pack. It didn't change a thing. Also the mechanic is waiting for a some kinda scanner from audi. I have a VAG scanner(Volkswagen Audi scanner) and all that brings up is misfire cylinder 4.
 
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Old 12-25-08, 02:01 PM
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Did he charge you for the intake gasket, part and labor, since that was not the problem? Some engine compartments are so cluttered up with stuff in the way that any replacement can be quite major, and naturally make what once may have been an easier less costly job, to be quite expensive.

When does the misfire occur? Idling? Cruising? Under load?

What did the old spark plug look like compared to the others?
 
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Old 12-25-08, 04:01 PM
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No didn't charge me for the time and labor of the gasket, just for the part which isn't that much. And yeah the audi engine compartments are very cramped. Misfire occurs anytime engine is running. At idle it is less obvious as it is just kinda a little shaky. When i give it gas it almost dies and the CEL will flash. It will drive if I keep it under 20 but really roughly. The old plugs were only a few months old so they didn't look too bad. Still replaced with new ones anyways.
 
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