Taurus Stalling - 99,000 miles, 3.0L, 2V group
I have been trying to isolatean ongoingstalling problems. What I have recently found out is that these problem happen almost exclusively when the gas tank has less than 1/4 tank of gas. The car will stall out at stop lights, it will just suddenly just turn off. It will also stall more often when driving at hwy speeds. When the car has 1/2 tank or more of gas, it does not happen. This leads me to think it's a fuel pump, fuel filter problem, or crud in the tank getting sucked into the pump or filter stopping the flow of fuel.

I have been running my Autoxray 5000 scanner, watching the real time, fuel rail pressure, while driving with less than a 1/4 tank. I have seen the pressure vary from 65 psi (highest at idle) to more of driving average of 36 to 42 psi. I always thought the fuel pressure should stay pretty constant while the engine was running (possible symptom).

Now I did experience stalling at a stop light, what confused me was that the scanner lost it's connection to the computer when the car stalled, which lead me to think it's an electrical problem. But why would an electrical problem only happen when I have less than 1/4 tank of gas? The only thing I can thank is that when the car stalls due to a lack of fuel, the computer resets causing a loss of connection to my scanner. This may be why it's so hard to find the codes or see if the fuel rail pressure drops to zero due to a failing fuel pump, or clogged fuel filter.

I am going to try a test by hooking up the scanner, starting the car, then pulling the fuel pump fuse to see if I can replicate the stall. I will look to see if the computer resets during the stall and I lose the scanner connection. If it does, I will replace the fuel filter, and fuel pump.

* If anyone knows if the computer resets at a complete engine stall please reply.
* If you are having the stalling problem check to see how much fuel you have in the gas tank when it happens. if it's below 1/4 tank please reply.
* If you have been scanning the car and see the same loss of connection when the stalling happens please reply.

I will provide everyone with the results once the "pull the fuse" test is complete.

 

Same problem here, hwy running and starts to miss when it gets to a 1/2 a tank. Replace the fuel rail pressure sensor and that worked for a little while but the wife has been driving it and she isn't driving much hwy and usually fills up before it gets to a 1/4 of a tank. Did you ever find an answer to your problem?

 

The reason that I joined today is to let you guys know how to fix this very frustrating vehicle computer reset problem. I fought the random crazy dash lights and stalling issue for over a year on a 2003 Taurus SES. IT IS A BAD DIODE IN YOUR ALTERNATOR Trust me on this. Replace the alternator. I did not want to post until I knew 100% this was it and after 12 months with no problems I can safely say that it is 100% fixed. I hope this helps I know that some people will still be skeptical as they have fought the problem for so long but if you replace the alternator and the problem continues then you have replaced with a alternator that also has a bad diode. The Guy at the local Autozone store found it with the store tester. I had been having it tested at Advance Auto parts and their machine did not show the bad diode. I wish I had written down the tester model for you sorry. I would go to several different stores and have them test for a bad diode in your alternator!! I searched for many hours on sites like this and NEVER found the definitive answer so here you go REPLACE THE ALTERNATOR and then have it tested to make darn sure you got a good alternator. Good Luck