i've searched and searched and can find no answer. stumbles until 2500 rpms then runs like a champ. does it in open and closed loop. and gets a hair worse with a higher temp. i've changed the tps, iat, plugs, maf , map, and both temp sensors. tested the knock sensor. i've changed all of these off of a 95 z to a 94z, none made any difference. i figure since it does it in both loops that it's not the 02's. i've got a msd blaster coil and wires, and i don't think that its them.. because it does it even when its not under a load. but at the same time it's not a miss. if you have any idea's i'm all ears... thanks! Mike

 

any help? this is driving me insane!!!

 

pcv valve and grommet? fuel filter. Changed mine the otherday bacause I was noticing a good bt of hesitation and only after 8000 miles my filter was bad gunked up. It made a difference. I am going to also get a gm parts pcv filter and grommet just for good luck as well.

 

What does it feel like when it stumbles? Does is vibrate at all?