OK heres the deal,i have an 86 Trans Am 305 TPI.I have a brand new IAC valve(adjusted properly),a brand new EGR,Hpertech coil,cap and rotor,new wires,new plugs corectly gapped and a new airfilter.The TPS is the only thing i didnt buy new.

And heres the problem.When i start the car it idles fine then all the suddenly it starts to break up and then it idles high and stays there then comes back down and surges and it runs rough again.Sometimes it will even stall when it comes down from idle.And if i try to give it just a hair of gas to keep it from stalling,the rpms shoot up like i almost floored the gas.Someone told me to test the TPS and heres what i found.

Its adjusted to .54 volts.But it seems like it never stays there.i can adjust it to .54 and start the car and come back the the TPS volts are off then.And i know the screws arent loose cause i tighten em good.So i tried to get the WOT(Wide Open Throttle) reading of the TPS and the volts were jumping.Id slowly open the TB and watch the volts go up from the TPS and theyre fine until i get to around 3.5-3.8 volts...Once it gets to about there the volts dont stay steady and they keep jumping from around .36 volts all the way up to 40.27 volts.And i know its not really getting that many volts.BUt it wont keep a steady voltage reading once i hit that point until i go aways past that point in the volts.So its like theres a point between idle and WOT where the volts are messed up and jumping around really bad,all the way up to 40 some volts.

Im not getting any trouble codes at all or a ses light.Do you think the TPS is bad and the problem with my car running the way it is?

 

Maybe yoy need a better meter, or your probe wires are bad.

 

assuming your meter is good, sounds like you have a bad TPS sensor!

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j.wolfe
_ ____ _
91 GTA L98
Best time: 14.389@95.49 (VIR)
"...Deception..." Brandon Sloan * ...wounds heal and chics dig scars...

 

Here are some more ideas for you. Did you take your plenum off? I found my IAC and EGR passages very diry. My EGR passage was totally clogged from carbon buildup. Cleaned it with a pipe cleaner and carb spray.

Also, check to see if your SES is working. It's just a bulb which may be burned out. I had a code 15 I didn't know about because my bulb was burned.

Consider your distributor pickup coil. They get old and brittle and will wreak havoc when trying to diagose annoying probs.

AND, have you changed your BUGGED prom. There is an updated prom to replace the bad one your car came with. Click the pic below, enter site, choose tips for the prom article.

~~~~~~~~~~~~~~~~~~~~
Red 86 T/A 5.0 TPI (LB9/WS6)
~HyperTech Cap/Coil/Rotor/AFPR
~Derale Adjustable Fan Switch ~ 170° Stat
~Flow Matched Injectors ~ K & N Air Filter
~Ported Polished Plenum ~ Runners ~ TB
~Polished Wheels ~ Alternator ~ Fuel Rail
~SLP TB Airfoil ~ Pirelli 245/50/16
~All Else Stock

 

OK,the meter is fine and i tried 2 other meters and theyre fine,so the tps is having a problem,but could that be cause this problem im having.

Yea i had the plenum off and when it was off i cleaned it up real nice.I had some big chunks of carbon in the egr and iac holes...But i used some carb cleaner and pipe cleaners and some other little tools i had lyin around to clean it all out,now the plenum is as clean as a whistle.And i know my ses light is fine cause even though the light dont come on,i ran a diagnostic test on the car and i get the code that tells you the sytems working,i think the code 12,and also its on when i put the car into accessories.So i know the bulbs not burned out.

Im pretty sure i checked the prom a while ago and it was a good prom according to the numbers,but i will double check it.So im guessing then either the TPS or the distributor pick up coil then.Now when you say the pick up coil,do you mean the actuall coil on top the cap???Cause mine is brand new,its the hypertech coil.Unless you mean the magnettic pick up,i dunno,im trying to learn about that stuff...lol...Im looking to get a new TPS anyways i think since i can grab one for $30.Then i can eliminate that being a problem.