Some background info. 1997 LT1 with 82k. Had to drive the car this winter a little until I got a new dd. Anyways, this problem has occured twice. I'll be driving and the car just shuts off. Kinda stumbles before it shuts off. After a couple tries at cranking it, it will eventually start again and run just fine. No check engine light comes on either. I took it to my mechanic and he put the OBD II scanner on it and he said everthing looked normal. The car idled fine for the whole time he looked at it and the whole way home (about 10 miles there and back). So the next day I go and drive it, it does it again. I have no clue what it could be? I just replaced the distributor last summer. Any help and insight is greatly appreciated! Thanks, Tyler

 

Possibly your fuel pump. Has your fuel filter been replaced recently? Might be that simple.

 

Test your ignition module. They are located on the cylinder head so they get heated up and somtimes fail.

 

Could still be your optispark. Just cuz you replaced it doesn't mean it isn't bad.

 

I'd say get a fuel pressure gauge and tape it to your window. Drive it and watch what happens to the gauge when/before it dies.

If i'm not mistaken, there should be some good fuel pressure even when you turn the car off, so if it drops to zero or decreases before it shuts off then well there ya go lol

If not, at least you can rule out fuel pressure stuff

 

Sounds like fuel filter.

 

Could be a failing ignition switch. $27 part from a dealer and a P.I.T.A. to change.

 

Correct, the rail should still have pressure, even with the car off. If the rail does not have pressure, then things such as a faulty check valve in the fuel pump, the fuel pressure regulator, or the fuel line in between the two can be of issue. That is assuming this is a fuel issue in the first place. As suggested, do a fuel pressure test. When the car is running, try wiggling on the ignition key, see if you can kill the car by doing that and that will be an easy way of telling if there is an ignition switch problem. Also, the ignition control modules can be sensitive to heat and have been known to cause shutdowns when overheated. It can be another thing to possibly check. If your opti was just replaced a year ago, I would lean against that, but it wouldn't hurt to inspect the harness.

 

What is norm for fuel pressure during idle? My mechanic checked it, and he said it seemed low to him, but he didn't really know what fuel pressure it should be.

 

At idle with the vacuum line detached from the fuel pressure regulator, the pressure should be in the 41-47psi range. With the vacuum line attached, the pressure can drop anywhere from 3-10psi.

 

I had one of the wires on mine that was loose and when I went to shift on occasion I hit the underside of the dash with my foot and it would kill the car took me a few weeks to find it but it was evident when I saw the plastic melting around the terminal so I got a new switch and put it in(replaced the terminal also).....P.I.T.A no doubt