I have a 95 6spd Trans Am with 101K mi.Since I've bought it I've done the following,New AC platinums,MSD 8.5 wires and blaster coil,AC fuel filter and O2 sensors,160 t-stat,carsound cat,K&N,Mobil 1 fluids,cleaned t-body,and I just put on a 1LE bellow because mine was torn.The car has been driving super stong until a few days ago when i noticed it was hesitating and knocking when revving at idle,I thought it was bad gas because it just started after i put gas in it,so I put some F.I. cleaner and water remover to no avail,but I noticed The problem was only when temp gets above 180,and I have no service light,anyway i disconnected battery and problem went away for about 50 miles until last night when it was back it is more pronounced when hot but once it starts its slightly there when cool.i disconnected battery last night,drove it this morning and its completely gone again even when warmIs some sensor getting to hot all of a sudden and the comp has to relearn?I looked at some previous similar posts but coulndnt find a clearcut answer.I'm stumped!Any help greatly appreciated.

 

I had the problem with the hesitation under load when hot deal. It was my opti. I can't say for sure if yours is, but that's what it sounds like to me. Mine would buck real bad under load when up to operating temperature and above, but would act normal when it was cold.

 

Your car sounds like my car. In fact, I did most of what you did, wires, plugs, 02 sensors, and a blaster coil. I found that my problem did get a little better but it still hasn't gone away. I'm pretty sure its the opti since Im still on the original one and it has 106k on it. It sounds like its your opti. In the morning my car feels so fast (normal), but when it heats up it sputters down low in the rpms and misses sometimes in the upper rpms. Im just affraid of replacing it now that some people are getting bad opti's from GM (See post above about bad opti's).
Zack S.

 

Thanks for the replys, but if it's the opti why is there no problem for the first 50 or so miles after disconnecting the battery ? I drove the car earlier and the temp got up to about 220 and there was absolutely no hesitation or sputtering and is driving perfect , but I'm pretty sure after driving for a little while the problem will be back and I will have to disconnect the battery again, any more ideas???

 

I think you need to check for a vac leak. Im having the same problem and my idle is getting higher and high Im pulling my intake off as we speak and replacing a few hose clamps and stuff like that dealing with vac going to the intake. I might have found it but I guess only time will tell

 

hesitation came back, disconected battery again,problem went away,Ive drove about 90 highway miles has drove perfect,(temp stayed between 170-180)but its getting annoying having to keep disconecting battery.Any more ideas?

 

i think its the waterpump. your water pump probably has a small leak, so when it is under pressure (hot temp) it leaks water right into the opti. then your car runs like crap. after a while, the water in the opti dried up and your car runs like new again.....may be

 

car is running like new after the computer is being reset by disconnecting battery,plus my car is not running hot(170 on highway) in 90 deg heat,although it seems it runs hottter than usual when it starts hesitating,but I'm sure its not the Waterpump.

 

[QUOTE]Originally posted by Burgundybeast
[B]how can I change my username while having the same e-mail?

 

check for error codes on your system. Maybe a sensor is out or connection is bad or you have a short in the system.

 

Okay,now I'm completely got temp up to about 210 deg,was sputtering,knocking off the line in 1st,and under a load in high gear, disconnected battery while it was hot,(220) drove around block and problem is still there I know I've disconected battery before, got temp up and hesitation was not there but now I'm at a loss,whether its a coincidence or not this problem was not there until I put on the 1LE bellow.Maybe it is my opti,but I would really like to know for sure until I spend my $.

 

like i said before, the opti might be wet, but all of hestitation problems seems to go away as soon as you drive it on the freeway, providing more air going through the radiator, resulting in cooler running temp and less pressure on the water pump. if you are running on the street, especially in a stop and go traffic. you depend on your cooling fan to cool the water. at that moment, your waterpump will work overtime and the pressure rise. a small leak and all the pressure causing the water pump to drop some water, not noticeable, but effect the opti......try turning the AC on, when the water temp just got over the half way mark, and see what happens.....hope that helps

 

It's the Opti...Maybe it started with the waterpump going bad, which in turn damaged your Opti.

Replace the Opti with a brand new one, and replace the waterpump as well, since you have it off...Bad waterpumps are usually the instigator to screw up the Opti's.

If you don't want to spend the $$, then you could do the cheap stuff first, like replacing the O2 sensors, EGR valve, replace vacuum hoses, , and after doing all that it STILL is causing you problems then guess what???

It's the Opti...

I don't think it's either the plugs/wires or coil or fuel filter because it only does it when it's hot, correct? Try replacing the vacuum hoses first, then the O2's & EGR, see what happens...

Good luck!

 

Okay,I checked all my wires to see if any were burnt,everything was fine,disconnected battery for a litte longer this time(last time was less than a minute),took it for a drive,now it does it intermittingly I swear,before it would act up,I'd disconnect battery,and it would drive perfect for awhile, its like I tried to trick my computer one to many times and its now wise to my tricksso I dont see how its my waterpump getting water on my opti then drying,or a bad waterpump because it drives at 160-170 on highway,or even my opti because it pulls strong,its just a stumble,and a knock off the line sometimes,regardless of temp,but is worse when hot, then goes away at high RPM,if it was the opti wouldnt it drive like $hit the whole time,but if it is what does resetting the comp have to do with the distributor?This is driving me nuts

 

I had the same thing, my car drove and ran fine when cold but as soon as the temp went up it stumbled and hesitated. This was after i replaced the coil, module plugs and wires. It was the damn OPTIcrap. Now it runs great. Now if i can just avoid rain ......