Couple of issues for 1999 A4 2.8 Quattro.... car runs great except at idle, I feel a slight vibration. Sometimes, the car takes a couple of seconds to start. Also, check engine light is on (I believe it's a cylinder misfire). Spark plugs, wires, fuel filter were all changed. Can this be the ignition coil?

 

get the code read at a local autozone or similar place most likely a bad coilpack

 

^^^what he said, plus while you are at the store getting your code read, grab some Seafoam and do the treatment on your car.

 

if your going to get some seafoam, you should change your sparkplugs too, i seafoamed my car yesterday and my CEL came on for misfiring on cylinder 1 3 4, i put in new plugs and the cel want away

 

SeaFoam doesn't foul spark plugs.

 

Its not the seafoam its the build up from the engine burnt off onto the sparkplugs caused by the seafoam.

If its the first time you have seafoamed the car new sparkplugs definitely recomended...

 

When I took my plugs out after seafoaming they were real gunky.

 

Update... the codes were showing misfires on cylinders 1,2,3.... we checked coil-pack and that was not the issue (could have sworn it was). It looks like it was the fuel injectors. Apparently, there was spark, but no gas being sent to the cylinders. I thought I was goiing to have to replace the injectors, but my mechanic suggested we service the existing ones, drive for a little and see if the misfires go away. So far, I've noticed a big difference, rough idle is virtually gone, engine is not as noisy, and sounds much smoother during idle and when I push it. And the treatment was just put in this morning. My mechanic says it should get even better the next few days. But if it doesn't, then the injectors should be replaced (ouch).

The CEL is still on, but it's not flashing when I'm driving, that means it's not misfiring, correct???? I'm new to the Audi world, so I'm learning as I go....

Any comments or other recommendations?

 

swap one of the bad injectors with a good one from a different cylinder and see what happens. yes, it means it's not misfiring. idk if the cam position sensor controls spark or fuel but that may be a possible problem. clear the codes and post any that come back.

 

dumb question.... how would I clear the codes?