I had an O2 sensor that seemed to test OK, but produced false "lean" indications at higher speed. Beyond that, the other sensors should be test-able.Well, turns out it was a couple of sensors going bad at the same time. The sad part is, they tested just fine. I finally said screw it and replaced them and it ran better after that. The sensors I replaced, aside from the obvious of the broken idle air control valve were the coolant temperature sensor, map sensor, tps, and o2 sensor.
HOW did you test them?
Possible--but unlikely--that a lifter would "collapse" with a "bang".I now have a new problem, which from what everyone has told me, sounds like collapsed lifters. What's wild is I was just sitting at a light and then there was a bang and now a mechanical tapping sound from inside the engine
Pop the valve covers, look for bent pushrods, loose rocker arms, broken valve springs. If you don't find valvetrain problems, you're maybe looking at a failed connecting rod/rod bearing; or maybe a cracked/broken flexplate.