I have 1992 GMC pickup that I bought new. It has

sounds like brain box or computer to me or could have broken wire to computer.

Replace the pickup coil in the distributor this is where you get your pulse for the injectors.

REPLACE SENDING UNIT THAT'S INSIDE THE TANK

yes a worn cam can cause it but it sounds more like timing off about 5 to 10 degrees

You may have been given the wrong thermostat. Either way, you can try a hotter thermostat. If the water pump has never been changed it might be time for a new one. I've already had one that was so old that the propeller inside had the fins rusted completely off and the bearings were so bad it was messing up the timing of the motor. The truck wouldn't idle. And guess where alll the rusted off propeller chunks ended up. . . that's right. In the radiator, heater core and the thermostat. I flushed that truck for three days in both directions to get all that scrap out of there. Good Luck. And if you still have the old thermostat you can always throw that one back in, just to see what happens.

Does Ford replaced the cruise control deactivation switch.
Vehicles involved in the recall include the following:

1998-2002 Ford Ranger
1992-1997 Lincoln Town Car
1992-1997 Ford Crown Victoria
1992-1997 Mercury Grand Marquis
1993-1998 Lincoln Mark VIII
1993-1995 Taurus SHO
1999-2001 Ford Explorer
1999-2001 Mercury Mountaineer
2001-2002 Ford Explorer Sport
2001-2002 Ford Explorer Sport Trac
1992-1993 E150-350 Vans
1997-2002 E150-350 vans
1993-1997 Ford F-Series pickups
1993 Ford Bronco
1994 Mercury Capri
2003-2004 Ford F0150 Lightning
1995-2002 Ford F53 motor homes.

Vehicles involved in the recall include the following:

1998-2002 Ford Ranger
1992-1997 Lincoln Town Car
1992-1997 Ford Expedition
1992-1997 Mercury Grand Marquis
1993-1998 Lincoln Mark VIII
1993-1995 Taurus SHO
1999-2001 Ford Explorer
1999-2001 Mercury Mountaineer
2001-2002 Ford Explorer Sport
2001-2002 Ford Explorer Sport Trac
1992-1993 E150-350 Vans
1997-2002 E150-350 vans
1993 Ford F-Series pickups
1993 Ford Bronco
1994 Mercury Capri
2003-2004 Ford F0150 Lightning
1995-2002 Ford F53 motor homes.

Timing at idle (degrees BTDC) 0 federal and 4 California (chapter 5, page 183, Haynes Chevy and Gmc pick-ups manual 1967 thru 1987) If you have any othe questions I have the manual, I have an 86 k10 4x4 w/350.

Sounds 180 degrees out. Move flywheel to top dead center. Remove timing belt and turn flywheel pulley ONE complete turn to top dead center. Then put timing belt back on with marks lined up.