Just wanted to see if anyone has had this problem. I just bought this 98 A4 2.8 2 weeks ago. When i got it it ran great but all of a sudden its misfiring in cylinder #1 and it sounds like its pinging. I didn't use the car for the 2 weeks. All I did was fill the tank with 93 and I wanted to change the battery with an Optima battery but it didn't work out. So the battery was disconnected for 5 min. As for the tank of gas I filled up with, its already gone and I filled up again with 93 form a different station and it still has the problem. On top of that I've changed the plugs with the factory spec'd plugs and new wires and I've changed the Timing belt, water pump, tensioner and pully and I've also changed the coil packs all six. And it still has the same problem mind you i've only had the car for 2 weeks. if anyone has any ideas I'd appreciate it.