Ok, my car has been doing this since i bought it. Its an M6 94 z28. Through the 1500-2500 rpm range it has a really bad hesitation, yet when i let off and give it gas again, sometimes it clears up. It doesnt really do it when the motor is cold, just after about 15 minutes of driving. I changed the passenger o2 sensor because it was shot. I ran throttle body cleaner through it, changed the plugs and wires... I am hoping my problem isnt the opti. Maybe someone could help me? Also, my MAF is de-screened.

 

SES light on? any codes?

 

sounds electrical to me since it does it when it heats up. probably coil or opti.

 

I am getting no SES light or anything...

 

I'd be checking my coil and/or opti. How old are the parts in question here? still stock? It might be time to replace them. Coils are cheap and easy to swap, opti, not so much...

 

Well... I have 2 cars right now so money is kinda tight. My 92 z is a lot easier to take care of than this... But from what I have heard most people say to change the whole opti while im down there... I mean if I just change the cap and rotor should it be fine?

 

I am having the same exact problem. It runs like **** to 2500rpms when its warm. I want to know whatsup before i throw parts at it. I actually took it to the Pontiac dealer today and they wanted to replace the egr and plugs/wires. I would not let them because i knew that they were just wanting to throw parts at it. Cant they tell where there is a misfire when they have the computer hooked up? How can we pinpoint the problem???

 

Hell yeah I want to figure this out... So far, i changed plugs, wires, one of the o2's and such and nothing diff so far...

 

id like to bring this thread to the top. my car is getting much worse. it idles horrible and doesnt hardly have any power. i dont drive the car everyday. does it sound like the opti to everyone? i cant believe i took it to the dealer just to have them want to throw parts at it, hell i can do that on my own. is there a surefire way to tell if it is the opti or coil going out? btw i have 107k on the clock.

 

I would probably change the driver's side O2 as well and possibly put a new fuel filter on if it hasn't been changed for a while.....

 

I just changed the opti on mine and nothing changed. it is still surging and running awful, it will not even spin the tires anymore. what else could it be without throwing parts at it.