My 1989 F150 has a 351, fuel injected, and I cannot figure out what in the world is wrong with it. About 4 days ago I changed the fuel filter and that helped for about 75 miles, then it started stalling again. New plugs and wires, new air filter, checked contact points on battery, I know for sure it's not the fuel pump, also checked distributer cap and rotar... I'm at a complete loss. When it runs it runs good, no misses or anything, but it has a bad habit of just dying while I'm going down the road, not good. If someone could help me, I'd be much obliged.

 

I had a 81 F100 that did the same thing. It was rust in the metal gas tanks that constanly plugged up the fuel filters. An 89 F150 has plastic tanks though.

 

Sounds to me like symptoms of the TFI module going bad... the same one (you may have heard) they are now reimbursing people for who have had this module replaced recently. The problem? The darn car will just shut off for no apparent reason. What happens (my understanding) is that the TFI overheats and, for whatever reason, stops functioning.

You probably have one of these on your '89 (mine's a '90, and I have had the TFI replaced). Look at the side of the distributor head... there should be this grey plastic 'thing' screwed to the side, with about 5-6 wires coming out of it. It's about 1.5" wide by about 4" long. You might need to replace it! I got a Mallory replacement from summitracing.com for about $48 plus shipping, and have had no stalling problems since then.

Good luck,
Chuck