Nancy

1991 Mustang LX 5.0 Automatic, standard size tires, standard rear-end gears.

I have had 3 speedometers that don't work. It says I'm going 38 when I'm going 25. It says I'm going 70 when I am actually going 55. Do I need a new speedometer gear?

When the car is driven in the 65 mph range, the car starts to lose power and has stalled 2 of three times, when I had about 1/3 tank of gas. The car re-started fine when 5 gallons of gas were added.

The car did not stall when I had a little over 1/2 tank of gas. I was going 65 mph. Then the car lost power and would only go about 50 mph. The car does not shake, hesitate, or make any unusual noises when it does this. I am pressing down on the gas pedal, the car just won't move very fast.

Is it possible I have a fuel sensor problem or a relay swich problem?

I just had the plugs and plug wires replaced.

ctgreddy

hmmm try changing the fuel filter as thats real cheap. If it does it after that check to see how much fuel pressure and volume your getting. Pressing on the gas but not moving fast also sounds like a plugged exhaust could be the problem.

mjr46

best thing to do is tape a fuel pressure gauge to the windshield and see what pressure does when prob occurs, it may have a pump starting to go out