Hi guys,

My 91 TA has recently developed a hesitation under normal rpm's. It bogs pretty bad especially around 1-1.5 rpm, and under full throttle the rpm's stick at about 3k. The car runs better when it is just warming up, but still not perfect.

Any ideas? I couldn't see any spark leaking out of the wires or anything.

Guys on here are gonna expect you've checked the usual.....make sure your ignition system (coil to plugs) is in good condition and not arcing anywhere.....check your TPS and IAC to make sure they're working right, check your fuel pressure and see if it keeps up, check your timing to make sure its set right. Check to see if your valves are set right, check for vacuum leaks, clean the intake manifold/TB, test your EGR, etc, etc. Test compression. Some other things to test are your ignition module and pickup coil. A lot of these tests require a standard multimeter. If you need more details just ask, but these are typically the things to check if you're having running problems. I'm sure there are more I'm forgetting. Past this brings into question the computer stuff, which gets hairy....

Maybe this kind of stuff should be in a a FAQ. I'm having the same sort of problem, did a search, and came up with fragments of info related to whats going on, even though its the same issue.

well it's been a while since a tuneup so today I put new wires, cap, rotor, plugs, and a ciol in. I also checked for vacuum leaks but found none. Tried to change the o2 sensor but didn't have a big enough ratchet. How do I check the valves? There is a new ticking from the top of my motor, don't know if it's related or not. The car now runs almost perfect when it's cold, but as soon as it gets to around the 195 mark it starts to be sluggish.

well today on my way to school I got lucky, my SES light came on. (first time in 3 1/2 years) Gave me a code 13, oxygen sensor circuit. I'm going to take another crack at it to see what solves the problem.

I was reading through the Pontiac manual and it pretty much said ignition, fuel, or a sensor.

ok how exactly did u get the rotor off? i am in the middle of my tune up but cant seem to get the rotor off. do i just use brute force and pull it off? i have an 87 GTA if it helps. 350 TPI. anyone? sorry i dont mean to take away from ur problem man.

yeah just pull up really hard, and it should come out.

I got the O2 sensor out with some pb blaster and a huge socket and extension. Also helped that the manifold was warm. Reset the ecm, and now runs a lot better.

Yeah just pull hard. I replaced mine and though the replacement was the wrong size, but it just took a lot of force the first time. Its a very simple piece, don't worry about it.