hello, new to the site and have found alot of good info. I have a fuel issue with my 03 cavalier and hope someone can help. After the car runs for about 30 mins, at idel the fuel pump relay opens and closes when it wants so it will loose fuel pressure and stall. So far i have replaced the fuel pump with a gm one,fuel regulator, oil pressure sending unit, icm, air intake temp sensor and fuel filter. I am out of ideas except for the pcm and I dont want to spend $400 to find out that is not the problem. Any help would be great. Thanks in advance

 

Change the fuel pump relay with another one that is the same and see if the problem goes away. Also check where the relay plugs in to see if there is corrosion on the contact or if the contact in the fuse box is pushed out of the way some.

 

Hi oldchevy, I have swapped out relays and fuse, also have cleaned the contacts and same problem. It seems that the coil of the relay is losing voltage causing the contact to open. If I hold the relay contact closed the car runs fine.

 

If your not getting a check engine light, and the relay is dropping out, I'd replace the crank position sensor. I had issue with my lumina, wouldn't start no cel, cps was the issue.

 

Ok, reading this again, let me ask, it does this at idle only after a period of time? Will it stay running at higher rpms?

 

It does it at idle, high rpms and while driving.

 

I'd still look at the crank position sensor