99 Lumina LTZ stalling issues

[maxwedge]

Originally Posted by rkvons

So you drive the vehicle around for 15 minutes, pull into a parking lot somewhere, put it in park, shut the key off, and then within 10 seconds try starting it and it stalls? Or do you have to wait about a half hour for it to stall when you restart it? If the answer to the first question is 'no', then a temperature sensitive vacuum leak does not sound like the answer. If the answer to the second question is 'yes', then this is what was happening to my wife's 3.4 liter minivan until I determined that her injectors were leaky and replaced them. Never had another problem since. I never heard that you disproved this theory, so, you just never know. The test for leaky injectors can be done in 15 minutes and you would know. Believe me, I could not believe that they would cause her car to act that way, but they did.

On target, not an usual problem on any of GM's 6 cyl. engines. Fuel pressure test at the rail can confirm this.

[DRJSP]

The fuel pressure at the fuel rail is 43 psi. Goes up to 50 psi when running if I remove the vacuum to the fuel pressure regulator; goes back down to 43 when I put it back on. Goes up by about 5 psi temporarily when you goose the engine.

Pressure bleeds off to 30 psi after 10 minutes of engine/ignition off and seems to hold there.

Yes, if I drive it around and stop for a while, then it stalls on restart unless given some throttle to about 1000-1500 rpm for a minute or two, then will be able to settle down into a smooth idle at about 730 rpm.

It may start right up if I try to start it immediately with no stalling. After half an hour, it definitely will stall on restart.

[DRJSP]

Problem solved...I sold it yesterday. Would have been interesting to see if the plastic intake plenum was the problem, but not more interesting than making it someone else's concern.

Thanks for all the help.