I have a automatic z24, just replaced fuel pump, pump now has plenty of pressure, a few days after installing, the engine starts, has rough idle for 10 seconds then quits unless I rev it up to keep it going, but will not idle longer than 10 or less seconds....tried checking it with obd2 but the obd port under dash has no power and giving no readings....have checked all fuses....any suggestions would be greatly appreciated

 

Hello,

Have you tried inspecting your PCV valve to determine if it's bad? A faulty PCV valve can cause rough engine idle or stalling at idle, as well as a decrease in engine performance including poor fuel economy, slower acceleration and an overall loss of power.

You can remove and inspect the PCV valve by shaking it back and forth. If the PCV valve is malfunctioning or is clogged, you will hear no sound when you remove and shake it. A functional PCV valve should make a rattling noise if shaken.

Furthermore, I would inspect the EGR valve to determine if that is properly functioning. (P/N **578036) A bad EGR valve can cause rough idle and in some cases stalling so if your PCV valve is operating properly then there's a chance that the EGR valve in your Cavalier is clogged.