I have a 01 f-150, 4.6L, with 160k miles on it. Symptoms: It idles fine with an occasional surge. It sputters in all gears like a misfire (all plugs and COPS replaced 2 months ago). Sometimes it stalls out going down highway or as I turn in my driveway. It also seems like its slipping a little without the "hard jerking into gear". Occasionally the rpm meter will peg low and then return to normal. The only code that I received was P1451. I changed the canister vent solenoid but the symptoms remain. I've checked voltage on the TPS (the variable voltage checked out but I didn't get the 5V ref. voltage). I've cleaned the MAF sensor. I've also changed the fuel filter. I've resistance checked the connector to the PCM and found several pins that are at ground. I'm not sure what to do next. Any advice or tips would be greatly appreciated.

 

Open the power distribution box near the master cylinder and push down on all the fuses and relays to be sure they are seated.
After this if you still have an issue, the PCM likely losing power.
It may be the PCM relay contacts.
Try it an see what happens.
Good luck.

 

I ensured all fuses and relays were seated properly and the symptoms remain. Is there a way to check the PCM relay other than just replacing it? According to my owners manual it is 304.

 

Another symptom I failed to mention is earlier today it stalled, the theft light was blinking quickly, and it would not restart. I turned the ignition off, sat there for about 10 minutes and then it cranked up and I returned home.

 

almost sounds like a bad fuse or crack in a wire. if you have a hairline(rare) break in the fuse it would intermittently work. my theft light blinks fast when im running out of battery.(i like to listen to the radio and party in the bed.

 

Try swapping 304 with 301.
If the relay acts up note a difference in the result.
You always need to give all the known observation details but not a lot of history..
Not restarting is significant along with the Theft lamp.
If the PCM loses power, the Pats 'becomes involved' after the fact, on restart because the two systems has to talk to each other.
Be sure fuse 20 and 30 on the dash fuse panel are seated.
Good luck..

 

Well I eventually gave up and took my truck to the dealership. They called today and said I had a bad coil and it was causing Radio Frequency Interference with the PCM. I'll find out for sure next week when I pick up my truck. In the meantime I bought a 2014 F-150 EB and I love it. If my 01 is fixed It's a win win.

 

Under certain conditions that is possible.
A faulty coil that propagates an interfering signal back into the PCM can upset or even stop it processing intermittently.
It often feels like a sudden loss of 12 volt power as if the ignition were totally cut off and on.
Good luck.

 

I had this same problem. mine started every once in a while it would act like it was going to die while idling. several times it did die, but never while I was driving. finally one day it did die and I couldn't get it to restart....the THEFT light was flashing. I work at a dealer and I was just about to go get the shop truck to pull me back so I could figure it out and it started. I drove it over there and grabbed the scan tool to see if it was something easy. no communication to the PCM, it wouldn't start, and THEFT light again. I left it for the weekend and got my brother to come pick me up. when I got to work on monday the techs were wondering why my truck was in the shop and I explained to them. several of the older techs said replace the PCM relay and it should fix it. they said those things go bad all the time on these trucks and like expeditions. sure enough I replaced it and no problem since. it definitely was a lesson for me.