2000 A8 misfire, and idle issue, PLEASE HELP
 

So i am new to the forum and have searched this issue butttt... i cant find a fix, maybe someone can help me.
ok, so i have a 2000 a8 throwing a cylinder 6 misfire. :mad:
i have been to the dealer and had everything replaced. (plugs, POS, packs, and wires). If i swap packs it still goes on 6. I have ran injector cleaner and sea-foam for carbon built up in motor. I CANT FIGURE IT OUT. :confused: I know some people have said the ICM? Does mine have one, if so where is it. Trying to find parts in these motors is a bit**.

Thank you all for your help. :)

Travis

First, if you don't have one, get a Bentley manual. If you're gonna work on a sophisticated car like this, you don't have the right tool if you don't have a manual. Even if a dealer does your work, it will make you smarter and less of a rip-off target.

http://www.ecstuning.com/Audi-D2_A8-...ch/Bentley_Cd/

Your car does not have an ICM...signals are sent directly to the individual combination POS/coils (one part) from the ECM, inside the electronics box, under cover in fresh air plenum passenger's side...might check there for moisture intrusion or bad connection on one of the multi-plugs.
Also a bad injector can throw the same misfire code at a given cylinder.

Well we ran a lot of tests and found the cylinder has 40 percent low compression. Basically I'm screwed. I'm pretty sure.....

Oh, not good...best case scenario is bad valve seating...or even better, a valve timing problem..correctable. Hopefully not a piston/ring problem (not common, but possible)...cylinders in these cars can't be bored out for repair.
Good luck.

Well, Thankyou for the help, some have been saying I might as well replace the head, but, then I might as well buy a new motor, or part out.

I'd want more definitive testing like cylinder leak-down test or look for a lifter stuck, bad valve, carbon, etc...and especially to check chain timing on that head. A good mechanic can determine the cause of compression loss...then you'll know the work/cost involved. Some have replaced heads or repaired valves/lifters, etc and still gotten long life out of the car afterwards.
Please update us if you learn more.

A p0300????
 

I can tell you want it is not, timing of the chain on that cylinder head would be out of question, because the engine is only misfiring on one cylinder. CLT is a must, before you spend any money. With my experience, if it is valve train related, look for a used head, and if it is a problem in the bottom end, low-mileage used motor. You will spend a good amount of money trying to repair a burnt valve, valve seat, faulty lifter and swapping out rings or bearings on the bottom end. Save yourself the headache and look for used parts. Or part it out or sale as-is.