Shutting Off

[Duck]

1991 Bronco 351w E4OD. This is my stepsons bronco and he has been experiencing a problem with it just shutting off on its own, sometimes it will restart and sometimes it won't. He says his tach starts jumping around and it dies like it was just shut off. It usually won't restart right away but if it does it runs poorly and has no power and the last time wouldn't get any engine rpm to speak of, drove it home at 15 mph floored. Everytime it happens to him it will start again by the time I can get there, usually several hours later. The only codes where 21, 45, 46. Any ideas?

[blue beast]

Gas line dryer 2 bottles of heet and 2 of iso heet. With a big gas tank and gas prices high it probably doesn't get filled up, Any empty space in the tank is condensing water from the air. Water has higher surface tension and will block small openings! If that doesn't cure it after 30 miles or so(ohh yeah dump it in the tank wether it is full or quarter tank) Clean the IAC! The reason it starts back up after a bit is that water is heavier and will sink back down until demand brings enough back up to block openings!
Gas line dryers don't actually dry the water up but lower the surface tension and allows it to be burnt in the engine!

[SC Car Dude]

It could also be your TFI module. If it is mounted to the distributor it overheats and will stall the vehicle.

[Duck]

Update: It's a wire harness issue. You can grab a hand full of wires under the dash and give them a wiggle and kill it. I had not actually looked at it until friday night when he brought it to my shop. Saturday morning he went and got another truck so we are going to part out the bronco unless someone local wants to buy it whole. Thanks for the help tho, we do appreciate it.

[SC Car Dude]

D'oh! If I had said to wiggle the wire harness it would have been a TFI module. I just can't win.