I have a 1999 STS that will die at idle after it warms up, but not consistently. It restarts immediately. It will not die as long as you keep a little pressure on the throttle. I have replaced the fuel pressure regulator. Thank you in advance for any help.

 

I might suggest to check the Fuel Pressure at the rail. There's a bike valve looking valve that can hook to a pressure gage. Can you check to see if any codes where triggered?

 

The fuel pressure was fine, 45#. I took off the coil packs and tested the resistence, all within the norm. I also had an old code #1377 which referred to the camshaft pulses. After taking off the camshaft sensor and taking it to the auto parts store, I had to order a replacement so I put the old one back in. Since then it has not died!. Will replace the camshaft sensor when it comes in. Thanks.