So ive had my 1988 camaro 305tbi with the auto tranny for 3 weeks now, and its been in the shop for 2 of that. it has one problem, it hesitates on first accleration and when going up a hill and when turning left, but it only does it when the engine is warm. it cost me 914 at the shop and they didnt fix anything. so, heres whats been fixed: new cap and rotor, new plugs and wires, new serpentine belt, adjust timing and idle, new fuel filter and air cleaner, and a new distributor ignition control module, and the kicker, a new engine control computer. and it still does it. sooooo, anyone out here got any ideas? im open to anything. ive heard about a bad or dirty tps being a cause of this, and so is a bad throttle valve cable, please help, im soooo confused and i need this car, its my dd.

 

Check to see if there are any bad dents, loose parts, bends or kinks in the exhaust. Ive seen this happen a few times on different cars.

Also check your batt cables and alt and make sure nothings grounding.

Just another off the wall thought, weak fuel delivery, FP or in tank hose?

 

it could be any of those, this mechanic isnt really good about calling me. i also looked a bit online and found a failed egr valve could cause it too. so....heres the laundry list of things to check so far

1.tps
2.t/v cable
3. egr valve
4. FP
5. in tank hose
6. exhaust
7. battery
8. alternator

sounds good. i just wish there was a tsb or something out there to fix this. because i need the car back. granted since the mechanic said it was fixed, and i got all the work warrentied, i wont have to pay anything else.

 

You should also prioritize that list. Easiest/cheapest first. Do the things you can do first, then let him if you havent found anything. Wouldnt be fun to drop a tank to find out you couldve just welded exhaust. GL!

 

the car is at the mechanics now. and i already told him im not paying anything more because he's had the car for 2 weeks and pretty much tuned it up, which any other shop couldve done in a day and guessed at what made it hesitate. i waited a week and a half, went through three ecus, and it still has this problem. this is the last time i take a car to any mechanic, i could look at a book and do it all myself, tbi isnt that hard of a system to figure out, but i needed it done fast and done right, well i got neither. so, what are the most common culprits for this? my grandpa had a 1986 olds that had a tps problem and hesitated when it went around a corner, going left. so does my car, but it also does it when the engine is warm and you first acclerate, so idk. im just confused/fed up.

 

Have you checked for any codes?

 

Might want to check the coolant sensor on the intake. It will be by the t-stat housing. That one controls the computer. Unless I am wrong yours will be the same as my 89 and the guage sensor will be in the drivers side of the block. I think it was between the 1 and 3 cylinders. So you know.
Also you could take out the IAC and clean it, and check the tps.

 

no SES light so therefore no codes. what about the coolant sensor though?

 

Checking TPS and MAP voltages would be first on my list and they are free and easy to check your self.

 

Are you saying you dont have an SES light or are you saying it isnt on? Just because it isnt on, doesnt mean you dont have codes. I dont have an SES light, but I have 3 codes stored.

 

The light comes on then goes off.
I don't think OBDI is supposed to store them if the falut goes away.

 

Then you deff have codes. And they do store. Check them... And let us know what comes up.

 

So you're saying the engine runs fine when it's cold, but hesitates and runs like crap when warm?

I'm surprised nobody has mentioned the O2 sensor. When the engine is cold the ECU is controlling the engine blind based on fixed fuel tables (open loop). Once the engine is warm and the ECU goes into closed loop the ECU starts using the O2 sensor for engine feedback. A bad o2 sensor could be consistent with poor warm performance. Might as well try it, it's only 20 bucks.

 

I thought of this too, but how would that explain the left turn issue? Maybe a combined problem?

 

$20.00 for an o2 sensor? That's not a GM unit. Don't mess with aftermarket. Clean the IAC , Replace the o2 sensor, replace the coolant temp sensor . The car's new to you, right. Who knows when these things were done last.

 

Cant you clean the O2 sensor as well? Never done this, just a thought. Because Im sure I need it done.

 

Bosch O2 sensors are $17 from Autozone or Advanced. That's the same brand that all of us use for WB sensors as well. Don't waste money by getting an O2 sensor from GM.

Similar to the argument of cleaning spark plugs. Just get a new one. IIRC, WB and NB O2s have small holes on the bottom that would make it quite difficult to clean the inside, besides not knowing if you damage something poking around in there.

 

How about an intermittent ground that's opening when the engine torques under load or while turning?

The O2 sensor is an interesting thought, too. The wire or connection could be bad and being pulled open for the same reasons.

Hopefully, pulling the codes will point you in the right direction.