After installing my headers in March, the car ran great (and I mean PERFECT) for 2-3 weeks. Then my O2 sensors crapped out, so I replaced them and it ran much better.....however, it still does not feel right. It idles rough in closed loop, and when I bring it to about 1500 RPM's in neutral, the RPM's drop 100-200 and keep going back and forth. This does not happen in open loop when the car is cool. No plug wires are burned. Could this be from an exhaust leak? With the converter locked, at medium throttle I can hear/feel a ticking coming from the engine.

I have checked the MAF, replaced the coil wire, fuel filter, the plugs and wires are new, and the O2 sensors are fairly new. The throttle body is not due for a cleaning either.

 

You figure in open loop its not using the O2s, could th ewiring to them be loose unplugged etc?, You may also have a vacuume leak , Possible?

 

The O2's are plugged in I'm positive..it wouldn't go into closed loop if they were unplugged, plus it runs better with them unplugged (I have no idea why). As far as I know I do not have any vacuum leaks