QuestionCar seems to run fine, but after driving for a short time it starts to stall out. It seems to just bog down and then chokes itself into submission. If I let it sit for a minute or two it will start up fine and run for a short time again before choking / stalling. The time interval seems to be related to the time it is allowed to sit. The longer it sits (unstarted) the longer it seems to run before it stalls. I sometimes can get 15 miles before I notice any problems, but once it starts it gets worse until I can only go a hundred yards. If it sits for a couple of days I'm good for another 15 miles or so before it start again.
AnswerYou've described exactly the symptoms of a failing fuel pump. The longer the pump runs, the more it overheats. When the problem begins, the more you press on the accelerator, the worse the car will run.
If you'd like to check for certain, you'll need a fuel pressure gauge and an adaptor to attach to the fuel filter. When running the fuel pressure should be 30 PSI or so. If you momentarily pinch shut the fuel return hose with needlenose pliers, the fuel pressure should spike up to at least 70 PSI. If the pressure is below either of those levels, you should replace the fuel pump.
WORDS OF CAUTION:
Prior to pinching the return hose, be certain it's in good condition and that the clamp is properly tightened. And only pinch it shut for a moment. I once did this to test fuel pressure, and the clamp wasn't tight enough, causing the fuel to spray onto the distributor and cause a fire.
