I bought a wrecked 2003 f150 with good power train that ran great before I replaced it into the 97 f150 and now it runs ruff at a idle and when I give it gas it runs ruff as well. I replaces the motor, trans and transfer case all at the same time. The new motor had 87,000 miles and the 97 had 208,000 miles on it. After replacing the motor trans on it, all I could see that was different was a plug that came up the right side of the motor that connected under the power distribution relay for the starter and the power that went to the fuse box. The plugs that was on the 97 was 2 bigger square ones with 1 smaller round one, and the one on the 2003 had the same 2 big square ones with the exception of the small round one was replaced with a larger square one, so I replaced the entire wire harness that goes under the hood and wrapped around the front of the radiator and almost back to the battery where it began. The fuse box was different and a lot of other plugs were different, (but didn't have anything to do with the running of the truck) like the horn and the impact sensor for the air bags, so I changed them from the 2003 over to the 97, that way everything worked. But after all that, I finally started the truck and it ran ruff. Does anyone have any ideas and do I need to change over the ecm or any other control module? I actually replaced the module that goes under the glove compartment and connects to it from behind the battery tray with a 10mm bolt that connects the harness and connector to the module and it did not start when I changed it out. So I put it back to the original one back in it and it still runs ruff. I would appreciate any help or advise on the matter. I thank you for any help you can give me. Thank you for your time.

 

i had the same problem in my truck and i thought it was a miss fire, but it ended up being a bad vaccum, have you tried checking that out?

 

so you used the wiring harness and everything from the 03..if so then you need the computer and everything that goes with..the computer in the 97 runs 2 coil packs, the 03 computer runs 8 cops.

 

The truck wont start with the 2003 ECM, it will only crank but the injectors/ignition are disabled because its still programmed for the PATS keys of the original truck it was in. You should probably put the 03 computer back in and have a dealer program your keys to match it. That would ensure the computer isn't causing the problem.

 

I have been switching cabs and motors and wiring harnesses on Fords for so long now, that I knew to check to see if it had a pats key setup, but stupid me, I only checked the 97 truck and it had a normal key, so I didn't think much more about it. But I just checked the 2003 and you are right, it has a pats key.
THANK YOU FOR YOUR HELP.
I can't believe I over looked some thing so simple, but it just goes to show you that it never hurts to ask for help.
I Cant thank you enough. I am sure it is the problem.

Does anyone know if I can change out the steering column and pats computer, to the 97 so they match and work without taking it to the factory? Because the 97 does not have the pats setup and I don't believe there is a way to program it if it doesn't come from the factory with it?
Or is the programming in the ecm? and the rest of the circuit is in the steering wheel?
Thank you for all your help and any more advice you have.

 

If you swap the PATS into the 97's steering column and swap the ignition cylinder from the 03' so that you are using the 03's keys, then it should work. But it will only work with the 03's keys since they are programmed in. If you don't have the keys for the 03' then you have two options:

Swap out the PATS into the 97 and have new keys made and programmed by ford. (in the PATS II systems which that truck would have it must be done with dealer equipment )

-or-

You can take the ECM to a tuner, and possibly have them shut off PATS in the tune. I know this is possible because i can turn the PATS system off in my truck and start it with a non-PATS key.