i have a 89 2.8 and it stalls while im sitting in traffic. i am replacing the TPS again since i got the car in august. could this be something else? symtoms: will sit at 1500 RPM sometimes then it will drop to 1000 RPM and almost die. it will drop below 500 RPM and come back up. if i give it a little gas while sittin at a light it will be fine.
thanks

 

It's the IAC.

 

could be the EGR or the FUEL delivery system turn the car on and find the egr and put your hand around the area if you feel a leak then its the egr

 

Had the same problem, I cleaned the entire throttle boby and the IAC, it runs fine now.

 

Before you replace anything, check for a vacuum leak.

With a leak the idle will go up because of the extra air, then the IAC will close off to bring the idle back down. The idle will come way down and the ECM will open the IAC back to a normal position, then the idle will go back up becuase of the vacuum leak.

You can replace all the parts you want, but if you don't do this simple check, you'll regret it if it is a vacuum leak.

 

it cant be a vaccum leak cause i had the car in the shop about a month ago and they fixed all the vaccum hoses. what is the egr and iac?

 

So nothing ever goes wrong after it's been in the shop???

Did they do anything with the intake manifold, brake booster, injector o-rings, or anything else that might leak?

I'm just saying, it's an easy test, you might want to check it out...

 

The 2.8 and 3.1 are notorious for blowby. That oil is recirculated into the intake duct and the oil clogs up the IAC and passages. Remove the two screws, or unscrew the IAC and clean the pintle with carb cleaner. Spray out the passages in the throttle body, and it'll run perfect.

TPI cars do it too, but for different reasons. Same fix. This is like FAQ simple and common.

If you don't know what an IAC is, do a search or get a shop manual. Understanding what it is and what it does would help your general understanding of the fuel injection system and how to troubleshoot it.

 

i replaced the throttle position sensor and that fixed most of the problem right away although its still not smooth idle. it does fluctuate a little. ill go ahead and clean out everything.

 

you should get a can of intake cleaner, remove the rubber boot off the intake. put some rags underneath the throttle body so you don't make a mess of your belt and engine. hold open the throttle and spray at least half the can in it. DON't get any in the other direction... re-install the rubber intake boot and crank it over. it'll take a bit to get it started and lots of smoke but it will make a difference at idle and when you are driving.
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or get garage to do it...

 

idle is fixed. it was a combination of a bad TPS and the ilde set too low.

 

so take the can of cleaner and open the butterfly and spray it inside the throttle body ?? all the way back or should i take the throttle body off and spray it? i have the same problem it keeps stalling the idle is ok sometimes but it will be fine just driving and it will just stall out i have replaced the fule sending unit and it still does it so wut do i do
sorry if i am jaking this thread im going to try all of that stuff that i saw on here