Hi guys, can a defective Throttle body affect the idle? The car is continuously hunting for the correct idle and always dies, even when I' m slowing down to a stop. The car has been repainted by the previous owner in the engine bay also, and I' ve noticed the cruise control cable was mounted too "tight" from the TB. For that reason, the throttle cable never reaches the "zero" position unless I push it on zero with my finger. Also, I tried too set the TPS on 0.54V without success. The minimus value is 0.75 or so. Time to change the throttle body in your opinion?

Thanks!

 

TPS is not adjustable. The cruise cable is, there should be five holes on the servo to choose from, if it still doesn't let the TB close you'd be better off learning to live without cruise control. Clean the throttlebody. Specifically, grab an old toothbrush and a couple cans of carb cleaner, clean the front and back of the throttle blade, scrub the edges of the throttle blade, scrub the bore where the blade sits at idle and remove the ridge of carbon and garbage that forms there. Clean out the passage to the IAC valve. Remove the IAC and scrub the pintle until it's clean, inspect it for wear, they tend to get a ring of wear where the pintle seats into the port in the TB, enough wear and you'll have an idle problem. Enough oily gunk and carbon from PCV/EGR and the IAC will stick and you'll have an idle problem. If after cleaning it still won't idle, you might consider replacing the IAC, or the throttlebody, or look for another issue that could be causing your stalling, like flaky Multec injectors.

 

Yes, I’ve been suggested to replace the Multecs already. I just want to be sure that the problem is effectively from the TB instead of injectors. Thanks for your help, I’ll let you know when I’ll done that!

 

The injectors can cause all kinds of problems, and the IAC along with the PCV vent dumping in front of the TB clogging up the works. I've never seen a 3.1L TB go bad, I'm sure it's possible, just unlikely. I have seen a ton of Multec injector problems. FWIW

 

I think I solved the issue, I changed the old throttle body with a used one bought on eBay.
The car now is much better in every condition and it no longer stalls. I keep having some annoying "puh" noise at idle, but at least the car is drivable again and it no longer stalls when stopping. Thanks for your help!

 

Maybe Drew can help me out on this one , cause he knows the history of these cars better than I do ;

The OP's avatar states he has a Firebird Formula , with a 3.1 V6 .
I may be wrong , but I always thought the V6 was only in the base model (Sport coupe) , and to be a Formula (Or Trans Am ) it had to have a V8 ?