1992 F-150 4x4 Black Smoke - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

Taxi_Todd · 11-25-2010, 10:43

Greetings,

I have a problem with a 1992 Ford F-150 4x4 with a 5.0 V8 EFI 125k miles.

Some days it will start and run fine, then the next day it will be difficult to start. When it does start it will blow black smoke while misfiring and popping. Letting it sit for a while sometimes cures the problem.

This is an intermitent problem and difficult for me to come up with new ideas to check. Any help or ideas would be appreciated.

**Bert** · 11-25-2010, 11:25

Very possible that it's the fuel pressure regulator. Unhook the vacuum hose and see what it does. It'll run rich with the hose off. Maybe the diaphragm is leaking.

**chipset** · 11-25-2010, 12:10

You are describing a leaking injector or more than one. Not unheard of in the 302 or the
351. In fact my 5.8 has a leaking injector or 2. Starts good one day and floods the next
day. A leaking diaphragm will flood the crank case with gas and BAD gas mileage. Have your injectors tested.

Taxi_Todd · 11-25-2010, 14:22

So far, unplugging the coolant temperature sensor makes it run normal.