Alright got a few questions for anyone that might be able to help. I have 85 LB8 305 recently purchased. It seems to have a somewhat of a throttle response problem. It only happens once in a while, but sometimes its bad enough that the car stalls. No engine codes whatsoever and other then a hard time cranking the car sometimes it runs like a champ. The basic things i can think of is that IAC valve has run its course for the age of the car, my 1990 did pretty close to the same thing and it stopped with IAC replacement, but im new to the TPI market so anyone able to help me. Thanks guys

 

Try some injector cleaner

maybe they're dribbling

 

Tried the Injector cleaner still does it, and i noticed after my drive tonight however that after the car is shut down, somewhere under the intake plenum it sounds as if a vacuem is letting out, i dont know if this is normal or not. Car runs good, but just wants to stall everynow and then

 

Possibly an EGR issue?

 

Start with the basic routine. Clean the throttle body, IAC, and IAC air passages. Set the minimum air position and TPS voltage. Instead of replacing the IAC motor, you can usually clean and lightly lubricate it with good results.

The "hissing" you are hearing under the plenum could be a leaking fuel pressure regulator relieving pressure back to the tank. It could also be an injector leaking down pressure into the intake. In either case, fuel injector cleaner additive rarely solves problems like this. Once the injectors are that bad, bottled cleaners just don't get it. If you do find injector problems, check out Cruzin' Performance for your options.

I'm guessing that the thorough cleaning of the throttle body and IAC will resolve most of your idle and stalling issues.