I have a 1999 Ford Taurus SE Automatic 3.0 6cylinder w/ 170,000 miles on it. She's been a great car, very little issues until recently. Anytime the outside temp. is above 75-80 and sunny she will undoubtedly stall after about 15 mins of driving, regardless of whether I'm idling or at higher speeds. The car will turn over immediately after stalling, but will then stall out again. If I let it sit for about 20 mins, it will start up and run for another 5-10 mins before stalling again. I can drive all day in rainy and cooler weather with no problems. I have been to three different garages, including a diagnostic specialist, but to no avail. I'm not throwing any codes. No check engine light. Good fuel pressure. Mechanics don't really want to start replacing parts because no one is sure of the issue. I have been recommended that it could be the engine coil, main computer, or fuel pump, but I don't really have the money to start replacing parts without a firm diagnosis. Any ideas? I would hate to get rid of this car, still runs great when it is running. Engine sounds great, good idling, AC still works really well, so I feel like if I can pinpoint the issue and get it fixed, I can get a lot more from this great car. Any help would be greatly appreciated!!!

 

With that many miles on it you have to put something into it.
Without knowing the vehicles maintenance history if you started replacing the less costly items first, like coil or crank sensor then the fuel pump you will still come out ahead.
There is equipment available to record what has happened and it will provide an answer as to what has stopped working. I would find another shop that can do that for you.

 

Is it by any chance a flex fuel vehicle? We have had issues with the fuel sensor on them.