Hello I have a 89 gmc k2500 extra cab long bed with the tbi Ok so I started having stalling problems when the truck would warm up now its from the get go when it's idling its real rough and when I push the throttle it seems to stall out but when I let off it purts back up and if its cold it will start fine and rev up but as soon as it to temp it start doing that I've replaced the follow parts cause I was lead to believe that it's a fuel problem Cap rotor wires plugs engine temp sensor idle air control valve tps map sensor injectors vacuum lines rebuilt throttle body with all new gaskets (egr valve hei module with used ones) that's all I can think if but I know there's more but I need assistance please any advice is useful

SOURCE: 87 chevy truck with TBI idles too fast

Spray the intake with carb cleaner to find the vacuum leak. Check where the EGR mounts and the throttle body gasket sense you had both off.

SOURCE: 1989 GMC 2500 5.7L - engine surges and stalls at idle. Loses power at cruising speed.

Wow you have replaced a lot of stuff. Lets go back to the Fuel pump. When you replaced it did you replace the hose between the pump and the sending unit. These are common for splitting. Have you hooked up a fuel pressure gauge to check what pressure you have? It should be real close to 13 psi and should raise to at least 18 or 19 when you pinch off the return line.

Marvin

• 85242 Answers
• Posted on Jan 16, 2011

SOURCE: pops back through the intake when it is cold runs

This problem can be caused by defective spark plug wires that are cross firing due to voltage leaking to a nearby plug wire as well as a flat camshaft lobe.

SOURCE: Erratic Idle - When starts the idle is about 1100 RPM as it warms up, it goes to 700 - 400 RPM

Have you "reset" the computer on the car. When parts are replaced, the comp continues to run the vehicle on all the old settings which can drive you nuts because nothing you do will fix a problem. Usually, taking both battery cables off and waiting for 15 minutes will reset the computer. If this does not do it, then ask a dealer how to reset yours.