Check Engine and Rough Idle
 

I have an 04 2.7T S-Line Quattro with 48k. Today while sitting at a light the car began idling very rough. Simultaneously, the check engine light began flashing. When I say rough idle I mean the entire car was shaking to the point it resembled an old rap video minus the air shocks. I pulled off the road and let the car sit for a few minutes which made no difference. The car continues to sputter with loss of power until I get going at a decent clip when it straightens out to a point. Even at higher speeds the car is rougher than usual and there's a noticable lack of power. I'm calling the dealership tomorrow. Not sure if I should attempt driving it or not? Anyone else had similar experiences? My gut feeling is that it's some kind of sensor. Car ran perfect before. There also is a slight hot smelling odor. All the gauges remain normal including temperature and oil pressure.

I noticed with the A4 I just purchased that if the oill fill cap or dipstick is not fully seated, it runs rough as hell. New to Audi - bt maybe something to check.

Would account for the smell as well.

If the check engine light is flashing that means pull over and turn off the engine.

It is most likely a misfire due to a bad coil.

What you need to do is scan the ECM with a vag-com or a generic scanner. this will pull the code explaining the reason the ECM sent a flashing CEL.

You can have them pulled for free at any autozone, advance, pep boys etc.. However if it is running like crap and still flashing you should borrow one or just go buy a generic one at the auto store they are about $100. The problem with generic scanners is they do not read all of the VAG codes (but it will read a misfire). For that you need a vag-com dongle available from www.ross-tech.com. I have also seen a cheapo at www.ecstuning.com that works with old 4.0 versions of vag-com I think we are on 8.0 now. I can't attest to how well that works but if you start another thread or just PM "midniteoyl" he has a cheap one. I bought the ross-tech it was $200 worth every penny too.

Misfire codes are P0300-RANDOM or P0301-P0306 last number denotes the cylinder misfiring. If that is the case take the coil off the cyl that is misfiring and swap it with the next cylinder. If the misfire moves to the next cylinder change that coil. If it does not change the spark plug. If it still misfires you will need to test the injectors, then the compression.

^^ What he said... follow the coils.

Bad coil

Identical Problem - Check Engine and Rough Idle
 

My 04 2.7T S-Line Quattro with 61k suddenly started having the exact same problem except the CEL seemed to go solid for a little while a couple times but mostly is blinking. I drove about 2 miles home since the problem began.

Thanks for posting and the replies. I will try this stuff.

It was coil #4
 

A cool little shop near my house fixed it for $150.

Did they tell you what the problem was? It may be nice to know...

(Sounds like a good shop to know, a stealership would have charged almost that just to put the codes!)

^^....

I've had the same problem a couple of times with my 03 A4 quattro. It was a bad coil, they tend to go bad on these cars so I've heard, and experienced. Not to mention the fire....