I have a 99 5 Spd, 62K miles, plugs changed and injectors cleaned at 55K, fuel filter not changed yet. First noticed problem in April (after filling tank), was accelerating (WOT) in 2nd gear and heard a "bang" (missfire) around 4K RPM. Problem went away, resurfaced for a while in June and now is back full time the past week (I filled tank again a week ago Sunday, only put about 100 Mi per week on car). I can accelerate at partial or half throttle past 4K RPM, but if WOT, problem. I "pushed" it Thursday while getting on RT 78 and got a series of missfires (?) and flickering chk engine light, which went out. Driving sanely now, not testing problem, I know it's there. Bad fuel, fuel filter or something else?

 

Well, lets see. You have a 99, your coils are garbage so I'd say they are the culprit.

 

Thanks Dave, any idea how much to have done @ dealer? I'm also going to do the fuel filter and belt, which should complete 60K mile service.