biggest pump
 

I've replaced the tfi module,pick up coil and ignition coil but my
stang still stalls after 45min-hour of driving (engine just cuts off)
no sputtering or surging. So I'm thinkin it might be the fuel pump
since it's humming pretty loud. What's the biggest pump I could
replace it with. the engine is stock.
thx in advance

Well I don't know what year your stang is, but my friend has a similar problem with his 95 Cobra. It turned out to be the cap and rotor on his distributor.

If you still think it is the fuel pump, I wouldn't go any bigger then 190lph since your motor is stock. If you get a 255lph, then you'll just have a lot of fuel in your return line. Keep in mind, you are suppose to hear the fuel pump "whine" a little bit.

I would check out the cap/rotor first because it's the easiest and cheapest thing to do.

oops the stang is a freshly painted 87 GT with a newer engine
(35k miles)

I'm in the middle of diagnosing the same problem. The car runs for about 45-60 minutes, and then it stumbles and dies in a matter of 5-10 seconds. After sitting for a couple of hours or less, it starts up and runs fine. So I figure it is likely heat related. My fuel pump is a 190 lph pump that I put in about 1 year ago, so it's unlikely the problem for me (I hope).

Here's what I'm going to do. I'm going to take a fuel pressure guage and strap it to my windshield wiper so I can see what the pressure's doing. Then I'm going to run it until it dies and watch the guage. If there's pressure there, then it's not the fuel pump or circuit. Probably in the ignition somewhere, and I'll replace the ignition module and see what happens. If pressure drops to nothing, I'll try replacing the fuel pump relay. Hopefully one of those two will fix my problem. Otherwise, I'll keep looking.

Anyway, you might check your fuel pump relay underneath the driver's side seat. They get pretty warm after you drive a while and might be the problem.

Keep guessing and plugging away. I'll let you know what I find tomorrow.

--nathan

i had a similiar problem which turned out to be a bad fuel filter had to replace it twice (maybe i had bad gas) but after that it ran fine no more stalling.