I am still dumbfounded about what happened this weekend. I took my early 98 A4 2.8QTip to Audi of North Atlanta Friday for its 30K service. After the service was completed, I was not out of the dealer 1 block before the car started backfiring and running very rough. The service advisor took the car out w/ me to duplicate the problem but it ran fine. He talked for 20 minutes about BP gasoline and how bad it is since I responded that BP premium is what my car burns and half of it has come from one station. I left again and got about 2 blocks this time when the symptoms reappeared along w/ the check engine light. This time I left the engine running until he saw the check engine light. <br>They gave me a new A4 2.8 FrontTrak Sport for a loaner. Sport suspension is too rough for the long driving I do but Dunlop SP8000’s are much better at quieting car, add a level of ride confidence, and should be standard equipment; atmospheres and interior lighting changes take the A4 to another level of luxury.<br>Saturday a.m. A o N. ATL called to say my car was ready and that they had determined that the spark plugs were bad. When I picked the car up it seemed to run fine until Sat evening when I was driving through a residential area. The transmission seemed jumpy between 20-30 mph; the voltmeter was going back and forth between 10-16; and when I stopped the car would not idle smoothly in Park. On the next trip, the airbag light came on and hasn’t gone out since but the engine and transmission seem to be smooth so far. I have an appt w/ another Audi dealer to have the airbag light checked out this week. Audi of N. Atlanta will never touch my car again.<br>I doubt seriously that there were 6 bad spark plugs and believe instead that they put in at least one wrong plug. Does anyone know how the control module would respond if there were wrong plugs? Is it possible wrong plugs would cause lasting damage and if so what should I watch for? Let me know any other suggestions. <p>

If you take really (I mean *really* !!) short trips in your A4, it can have adverse affects on the spark plugs. I was told this is because the Audi engines use a lot of fuel on engine start-up, and if you don't drive the car long enough to burn this extra fuel, it will foul the spark plugs.<p>I had this happen to me one time when I moved my cold car from the garage to the street, and then turned it off. The next morning, the "check engine" light was on, and the Audi tech said that the computer was reporting "random misfire" in one cylinder. This was believed to be due to the fouled spark plug.<p>I suppose that if you did this often enough, more of the spark plugs could become fouled, but, the check engine light would have come on early in this process. So who knows? This doesn't sound like it's the same problem you have, but I thought it was worth mentioning.<br>

Hey Tim,<p>Go to Jim Ellis Audi of Atlanta (Chamblee). I have always been extremely satisfied with the service there. Ask for Lee Wertz. I just had my 30,000 (1996 A4QM) performed last week.

Not to scare you but I will tell you this, my friend and I took a trip to Vegas, he just changed his plugs. Well, they ran too hot, and melted a hole in the chamber. It was crazy, they pulled out the plug and the tip was gone. They pulled out the cylinder, and there were holes everywhere. It was just 1 bad plug but he had to get a whole new engine.