2000 malibu quits running differant conditions

[lkraus]

i have seen this basic post on here many time, just none exactly similar, i have a 2000 malibu, and while driving the engine will simply shut off, the theft light does NOT come on when this happens, i have tried using only one key to eliminate an issue with the passlock system being activated ( due to to much weight on the lock cylinder. I have also installed a car chip to monitor the ECM, it's data output simply reads as if the car was shut off.
There is no common set of circumstances which seem to cause this issue ie time of day, rough roads, amount of fuel in the tank etc, etc.

When the problem first showed up it would only appear to happen when the tank was below 1/2, now it seems to happen even with 7/8 tank.
The only constants i can come up with is that adding 2 - 3 gallons of fuel, and the car drives normally again ( kinda eliminates any issue with the ECM, relay etc. or for the most part anything electrical), when the car quits it will then only restartr after about 10 minutes but then only run about 1/2 mile down the road, and quit again. it will do this until you put some gas in it. ( ad yes the gauge is reading correct).

I did put a pressure gauge on it finally, it reads at idle 48 - 52 PSI and is constanly "twitching" while idling, applying throttle causes it to smooth out to around 46 PSI. I also disconnected the regulator and the PSI reading jumped to around 60 PSI.

If i bleed off the gauge with the engine running, it will init. drop and hold at about 30 - 25 PSI then after a few seconds, drop to 10 PSI and start fluctuating wildly between 0 and 40 psi, the engine will then quit. Cycling the ign key on and off will not cause the pressure to return until you have cycled the key several times, ( and yes i can hear the pump come on during this ), abrubptly the pressure will return ( 50 psi static ) and the car will restart and the guage will again fluctuate wildly for about 10 seconds, then stabilize to the above readings and run like normal.

any thoughts / ideas does this sound like the pump is on it's way out and is simply quitting or unable to maintain under a demand load ?

[maxwedge]

Repl the pump and filter, nice job checking it out.

[lkraus]

anyone happen to know what the basic fuel delivery rate for theses cars is? IE GPM @ a given PSI ?

The only other peice of oddness was when purging the fuel, as pressure dropped below 10psi there was air in the line. Not sure how that happens any ideas?

[Berty72]

when the pump starts to go i may cause the fuel to airrate is my only thought.

[taylor1354]

the same thing has occured to my malibu. Dare i ask where to find the fuel pump on this car? just so i know what im getting into..Also, did changing the pump and filter get the job done?

[maxwedge]

Welcome to AF. This thread is 9 months old start a new one, please. Pump is in the tank, BTW.

[taylor1354]

call me stupid but i cant seem to figure out how to do that

[INF3RN0666]

If you're using up too much gas, you might want to check your fuel lines for a leak, and maybe the filter. Sounds to me like the pump is working hard to maintain pressure.

It could be a dying pump. However, you should know that these cars are placed under taxi load (running 24/7) and they perform better than some cars out there.