Just bought a 2005 s4 with 52k on it. Drove the car for about 1500 miles then had the check engine light come on. All highway miles with no crazy racing or reving. Took the car in for diagnostics check and was given the following codes
16684 P0300 001 Random/Multiple Cylinder. Misfire Detected. Sporadic.
16692 P0308 001 Random/Multiple Cylinder. Misfire Detected. Sporadic.
16815 P0431 001 Warm Up Catalyst. Bank 2 Efficiency Below Threshold. Sporadic.

I have no clue what causes these problems and have just run out of warranty. I am guessing the last one involves the catalytic converter temperature.

Kicker is, now the check engine light flashes, have no power and is pretty much not even drivable now. Sounds very throaty and hardly gets going in any gear.

Any ideas what to do next before it goes to the only Audi dealer inmy area that will charge me an arm and a leg to fix?

 

Chances are you have the original spark plugs still in there. I would get them swapped out.

 

I swapped out the plugs. 7 of the 8 looked to be original. The 8th one was totally different. Still the same bog down ride and no power. Check engine light still flashes. Anything else that is simple that could be the problem?

Thanks

 

That sucks! Try & unplug the MAF & take it for a little spin. When does the misfires happen? When cold, hot, idle, acceleration?

It might be a bad MAF reading, coil amps, CTS, vacuum leak, bad O2's, etc...

 

I had a very similar problem on my A4. It was the Ignition Control Module which is a little piece that sits on top of the airbox (on the A4 at least). Dealer wanted like $700 for it and I bought it off ebay for $75.

 

I am guessing now that the misfires happen all the time. It starts good, idles well, then once you get going (high or low revs) it just wants to sleep. Not sure if this will help solved it but obviously with the long drive I did the gas mileage seemed to be alot worse than expected. I know its bad to begin with but when in 6th and doing 80 miles and hour is 3200rpm normal? Other than that i am not too mechanically inclined to start check MAF's, coil amps, CTS or O2 sensors. I only have one dealer in my city and they are hard to deal with.

 

The question is, should I mess around trying these different things or can my dealer diagnose it faster and then get right to the problem for cheaper?

 

i am leaning towars eitheran ignition coil(s) or the MAF..... sorry to hear your having problems with your new car though.... when i first bought mine i had problems too... first the MAF then the TPS.... all good now though..... if i were you i might take it to the dealer and at least have them tell you exactly what it needs, then decide if you can do the work yourself and buy the parts elsewhere so you don't get raped by a 200% mark up..... good luck and welcome to the forums

 

Check the Yellow Pages for a Independent. Yes, they will be much better at finding the problem. Since you are not mechanically inclined, take it in.

 

Thanks guys...I'll let ya know what the problem is once I get it back.