Ford Repair: 92 Mustang runs then dies after its hot., fuel pressure gauge, throttle position sensor

Question
Hi,

I've got a 92 Mustang LX 5.0. The engine is stock and has about 90 K miles. Up until a few weeks ago it has been running perfectly.

Over the last few weeks I started to notice that sometimes under light acceleration the car sputters. Otherwise again it would drive perfectly.

Then one day at a red light it shut off. I tried to get it to start and after a few moments it started again and ran great.

Just the other day it started right up in the morning and ran great for about 20 minutes or so. Then started to sputter again under light acceleration. Stopped at a light and it turned off again, then I could not get it to turn on again.

If I try to start it now it will probably run great but after it gets nice and warm it starts with the trouble again. I have stopped using the car for fear that it will leave me stranded again.

My guesses are: bad fuel filter, or, failing fuel pump, or, distributor is failing??

What do you think could be causing this? How can I trouble shoot it?

Thanks!


Answer
My service manuals only go back to 1995 for Mustangs.  But I'll try to give you some advice.
It could a bad fuel pump, sometimes they start out by failing only when they get hot. I don't think the fuel filter is bad, it would cause problems at all temperatures if it was clogged, but I would replace it if you replace the fuel pump.  You would need a fuel pressure gauge to test the fuel pump.  I would also have the electronic engine control (EEC) system scaned for diagnostic trouble codes (DTC's) before replacing any parts.  It could be a bad engine sensor like the Throttle Position Sensor (TPS).  You would need a few special tools to troubleshoot this, like a fuel pressure gauge, engine scan tool, test light, volt/ohm meter, and service manual. It may cost more to replace parts than have a Dealer diagnose the problem. It usually costs about $75 for diagnosis.  I see people regularly for diagnosis after they have spent a couple hundred dollars replacement parts.
But testing the fuel pump and the throttle position sensor is where I would start.

I hope this helps,
Dave