I have this pickup that has a "new" engine it that ran fine in another f150 . Well, here is the history . The pickup had a blown engine in it (Fuel injected 302) and sat for around 2 years . I found a good running 302 that was running fine in the pickup (another 1986) . I got the engines swapped and it ran fine for the first 150 miles or so . Well, this is the story now, you can start the thing and run around 2-3 miles and it runs fine. Then it will start to bog down and loose power until it wants to die . I think it is a fuel problem but am not for sure. It will eventually die and not want to start . I have been told that it has a fuel pump in each tank and then a high pressure one along the frame beside the fuel filter (which I have already changed). I have put a can of heet in each tank thinking maybe it has water in the fuel from sitting but it didn't seem to help .
Any previous experience would greatly be appreciated and/or suggestions and comments. Thanks, Raz