Hennessy

Hi everyone Im James Im new to this Awesome fourm. I have a 1996 K1500 5.7L & its been a great truck its got 211,500kms, but lately It is idling very high it likes to accelerate up to 40km/hr without touching the pedal, the cel flashes only when i start it up and after 30secs of driving it goes out. Ive replaced the Tps, Iac, wires, Plugs, Cap & Rotor, Pcv, TB Gasket. Im taking it to a shop on wedesday but im hoping i figure it out. I just had a 360 spinal fusion or i would fix it myself any advise is greatful.

Thanks
James H.

oldchevy

Look for vacuum leaks or disconnected vacuum line.

cleveland63b

i 2nd the vacuum leak but would also pull the code(s)

Hennessy

I also have alot of suction when I remove the Oil fill cap it almost dies I only get the po507 and i have cleared it bought a new Iac and it keeps coming back

oldchevy

These are possible causes. From another site.

- Dirty throttle body
- Electric throttle control actuator misadjusted or damaged
- Faulty Electric throttle control actuator
- Intake air leak
- Poor electrical connection to the Intake Air Control (IAC) valve

johntaps

There are many reasons for po507 code coming again and again even after IAC has been changed. Have you checked the IAC motor connector? If it is ok then check for any open or ground IAC circuit.

Hennessy

Where is the Electric throttle control actuator located ?. Ive cleaned the TB right up & sprayed TB cleaner all over the engine with it running and got no change.

Thanks for the replies

Hennessy

Off to the shop hopefully they will figure it out!