My 89' F150 5.0 is shutting off at stop signs, red lights when I approach them, and slow moving traffic under 10-15 mph etc. If I keep the brake pressed, and press the gas to maintain approximately 1500+ rpms it doesn't cut off. It also idles fine and drives fine at highway speeds. It is only after I get going and stop or slow down in traffic that it starts sputtering and shuts off. My initial thoughts are fuel pump, throttle position sensor, and fuel filter. Any thoughts ? Thanks

 

Sounds like a defective brake booster or defective pipe to the booster. When you first press the brake pedal can you hear a hissing sound?

 

i haven't noticed that but will take a look/listen. How will the brake booster cause the vehicle to sputter at low speeds coasting less than 15 mph even if the brake is not pressed? ( that is what it is doing as well).

 

How about the idle air control?

Have you check for codes yet?