I have a 04 f150 new body style w/4.6 motor. Recently I had the number 3&8 coils and plugs go out while on the road. I replaced and the codes went away. We'll now my truck idles rough in park unless u slightly mash the gas and when you put it in gear you can mash the gas to the floor and it hardly runs and will barely pull itself. I'm stumped!!! I'm replaced all the spark plugs, new mass air flow, cleaned throttle body and intake tube, 2 new coils, eliminated the cat converters ( thinking there may be a clog), and even serviced the trans thinking maybe the torque converter was sticking. Ive ran a smoke rest and didn't find a vac leak. Any help/ words of wisdom would be appreciated

 

It looks like you have covered a lot of the basic maintenance on your truck, but what about the fuel filter? Extremely clogged fuel filters will cause issues. What kind of plugs did you use, our trucks like motorcraft. Also, did you disconnect the battery when working on the throttle body, if not, then I would disconnect it for about 30 minutes then try the battery relearn process. Did you take the throttle body off when you cleaned it, if not then all the crap that was cleaned went into your intake. Check all of the electrical connections and make sure that they are on correctly and click to lock. Also, get your truck up to operating temps and cycle through all the gears a few times, put it in Park and recheck your trans fluid level. Let us know how it goes.
Tom

 

Have you checked the FPDM? (fuel pump drive module mounted on the frame above the spare tire). They usually corrode and fail due to water in the electronics or they just fall apart.

 

how did you eliminate the cats being clogged .. you have 4 correct

 

Yes sry forgot to mention I've changed the fuel filter. And each time we fixed/ replaced something we unhooked the battery and reset the system. Last night when we changed fluid and filter in trans. I did it cold and then ran it to temp and rechecked levels. I tell ya it's blowing my mind

 

As Techrep asks above, how did you eliminate the cats being the issue? You say you lost a couple coils while on the road, did the issue feel the same or was it worse after the plug/cop change?

 

I feel like when he said "eliminated the cats" he meant removed them. I could be wrong though.

 

One cat had broke down and had a rattle about a year ago so I had straight piped it on one side. So I in hooked the other the other night. The only thing left is the resinaters. What does the fuel pump drive module look like and what does it actually do?

 

https://www.f150forum.com/f4/fuel-pu...-yours-152908/

 

It's up above your spare tire. Little black box. Remove it from the frame rail, and look at the backside of it. They corrode out, and let moisture in.
I assume you have no check engine lights on. What did you do with the O2 sensors when you messed with the cats?