I have an 86 ranger with a 2.9l. It sits alot now but when i do drive it, sometimes it will run super rich and have no power for about 15 seconds then clears up then does it again over and over. Seams to be when engine is warm. Now the other day i took it to the store and was sitting at a stop light and the idle started going up and down from about 800 to 1500 then stalled, It wouldnt restart for a few minutes. While trying to start it, it would sound like it wanted to start barely but wouldnt. Finally got it started and turned back home, Any ideas, im going for about an hour drive this weekend and need it working.

 

could be the computer is switching to the preprogrammed table after reaching the limit of adjustment. In other words, the computer has learned to run the engine even though the engine is way out of specification but every once and awhile it gets off the grid and has to revert back to the "limp home" program.

 

Pulling code on these are a pita but it can be done, try pulling them and posting them. In situations like this Google is your friend. So is FTE, but we need codes.