5.7l tbi engine problem(surges)

[boxchevy]

i have a 92 silverado with a 5.7l tbi automatic 2 wheel drive. My truck starts and runs fine when its cold but once it warms up it starts to surge at low rpms like when im driving in a parking lot or at the drive through. also when im going like 50 kms/hr it surges when i let go of the pedal, then it catches idle. anyone have an idea of whats the problem?

 

[dirtridinz71]

Try unplugging the hose off the EGR valve. It may set off a code when cruising for any distance.

 

[boxchevy]

i did unplug the hose on the egr valve and it worked and it didnt set off the engine light. so does that mean i need a new egr valve? Thanks for the suggestion.

 

[Johnbalderas90k1500]

YOU ARE PROBABLY GETTING VACUUM AT IDLE WHICH IS BAD. YOUR EGR SOLENOID COULD BE BAD CHECK IF YOUR GETTING VACUUM AT IDLE TO YOUR EGR. IF NOT WHILE YOUR TRUCK IS IDLING APPLY VACUUM TO THE EGR IF YOUR TRUCK STARTS TO IDLE ROUGH THEN YOUR EGR IS GOOD. YOU CAN ALSO MOVE THE DIAPHRAGM AND CHECK IF IT MOVES FREELY. IF NOT YOU SHOULD BE ABLE TO CLEAN IT WITH A SOLVENT.