Next time this happens, stop cranking, turn the ignition switch all the way to off, not just to "run", wait a few seconds, turn the witch to "run", (you should hear the fuel pump run for one second), then crank the engine. If it starts right up, dropping fuel pressure may be the problem. GM has a lot of issues with pump pressure. Chrysler, hardly ever. Low pressure would be the result of a problem with the pressure regulator, and Chrysler has almost no problem with them either. They commonly leak on GM vehicles. You know; the ones they advertise on tv how good they are?
You will need a fuel pressure gauge to monitor pressure when the vehicle sits for a while. If pressure comes up to normal as soon as you turn on the ignition switch, that isn't the long-crank problem. If you see the pressure dropping over time when it is sitting, use a hose pinch-off plies to pinch the return hose from the regulator to the tank. It's the smaller of the two fuel hoses between the body and engine. If pressure no long drops, the regulator is leaking. That is an irritation, nothing more.
If pinching the larger supply hose stops the pressure loss, the check valve in the pump is leaking. Another unharmful irritation. Both of these are very uncommon.
The more common cause of pressure loss is a leaking injector. It can cause a tempoarily flooded-type condition but typically for only one or two cylinders. Your mechanic can remove the injectors with the fuel rail so they can be seen, then he will watch for signs of wetness on their nozzles over time.
Tuesday, March 23rd, 2010 AT 4:55 PM