Marc3.4V6

iTrader: (1)

I have read almost all of the threads on rough idle and still have issues. So the day I buy my car, I noticed at stoplights the idle felt a little on the aggressive side for a stock internals car. Sometimes uneven roughness, sort of a kicking feeling in your seat, or like airplane turbulence. So I have replaced the plugs with ngk tr5gp, msd wires, changed fuel filter, cleaned air filter, MAF, IAC and TB. No change. It almost feels a little worse, I get scared it's gonna stall at long stoplights. I don't own a scanner yet but I used a MAC scanner at work and on bank 1 my 02 sensors were all over the place low to high (.01 to .89) and bank 2 sensors were steady at .85 in closed loop. Does this mean they aren't working right? I have no trouble codes. The tach indicates that in drive when warm that the car is idling under 500, but the scanner indicates 550 rpm with slight fluctuation. I also get a rough rpm drop at times when going between reverse and drive.

What else should I check, fuel pressure? On one occasion on a cold morning I could hear my pump whine after startup and the whine increased in frequency as I touched the gas pedal for a while until the car got fully warmed up. It hasn't happened since.

CHADsterss

Vacuum leak maybe?