I have a 92 Lumina with almost 300000 miles on it. I drove it to the grocery store and it drove as it always does. Some times it decides to quit running for no reason at all at any speed and usually always dies at idle so I always have to drive with both feet to keep it running, but other than that it runs like a little racecar. After stowing my groceries in the car I try to start it and it did try at first to fire up but then just acted like I had run out of gas. The gas gauge was half tank which is about what I figured should still be in there so I left the car overnight and had to come back with the trailer and pick it up the next day. I figured it was a fuel pump or filter or relay problem but this is its condition at this point.
1. There's gas in the tank
2. The relay's fine because the fuel pump runs when the ignition is switched to run
3. The fuel filter was extremely dirty but I cleaned it out and it made no difference in the amount of fuel delivered
4. The fuel line when disconnected at the throttle body delivers fuel for approximately 1 1/2 seconds when the ignition key is turned to run, then it apparently is switched off automatically.
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I thought that the fuel pump was supposed to deliver fuel until it's told to quit from adequate pressure obtained or something? But it only delivers a small amount of fuel for a short time each time the key is switched from the off to the run position . It does nothing unless I wait between each attempt for at least three to four seconds.
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The car apparently is not being delivered an adequate supply of fuel in order to start because it refuses to start. If I disconnect the air intake and provide fuel manually the car starts right up and will respond correctly to throttle positioning. Can anybody give me any ideas on what is shutting down the fuel pump after 1 1/2 seconds every time I switch the key to the run position, shouldn't it continue running? Thank you very much for your time I would appreciate any response, Scott

 

you said you cleaned the filter? try replacing it.
as for the little bit of fuel coming at first key of the ignition, it does this to pressurise the lines, then once the computer senses the engine is running it will supply more fuel, what i dont get is if u have a fuel supply at first key of the ignition, then why wont it fire at all unless fuel is manually suplied, im stumped, but i hope i helped with understanding a little better