Dina

Hi I have a 2004 Ford F150 Super Crew 4x4 5.4 V8 it has 120,000 miles . When I go up a hill it looses power and gets down to 40mph. It also misses and makes sort of a thrashing noise.It doesnot have any check engine ligts on and no codes are found. I took it to the Ford Store and to date have had the following repairs made using all motorcraft parts...New plugs,New fuel pump, new throttle body,new timing chain and guides, they took the catalytic converters loose and they are okay it had an exhaust leak so I got that fixed new gaskets and all {sounds better anyway} . The home remedeys we have tried is fuel injector cleaner, and the sea foam trick thru the booster. Still the samething. Flat level ground it runs and sounds great,at idle no misses. If any of you have any ideas I will be eternally greatful I have spent a small fortune and at the ford stores rate of 125 per hour the process of elimination is bankrupting me I cant simply sell it I live in the mountains and everywhere we travel is uphill LOL. Thank You in advance for any info you may have

Masi1926

Coils aren't on the list. It's usually one of them. It's always the coils...

kanga2311

It could be the coils, check the FPDM above the spare tire, clean MAF and throttle body with MAF cleaner. Take off all your coils(1 by 1), check to make sure a plug didn't come loose, check all the boots on coils for cracks(they can be replaced for about $5 each), and re-install using di-electric grease on the boots. A cat still could be plugged without hearing a rattle. Also replace the fuel filter if you didn't when you replaced the pump. It could be o2 sensors also. A lot of ideas, just tackle them 1 at a time. Good luck.

Dina

Kanga2311 What is a FPDM? How do I check?They put a new throttle body on a new fuel pump and filter. They put new spark plugs but the coils have not been changed checking those now I was told they had to be good if I had no check engine light. It only misses and the engine bogs down when going up hill or if you really get on it hard acceleration however sitting in park you can rev the engine hard with no miss or noise . Please keep the ideas coming. Thank You and God Bless.

Masi1926

That's not always true, I had a bad coil and my light would only flicker when I held it wide open. I would bet money on the coils, besides your due for them anyhow. The fuel pump module is located on the top of your axle on the drivers side. You can order one from amazon cheap and its a quality part.

kanga2311

I'm betting that it's clogged cats. But check/probably replace the fuel pump driver module. Make sure you have grease on the cop boots. Follow everything else I said before replacing cats. Those are expensive and all the other things should be done periodically anyway.

Dina

Kanga2311 Last night after your message the hubby went and took the FPDM off and you were right it was badly corroted and actually had the control board inside bent {he is an electrician and has understanding of how this thing worked} he too the bent casing off and hooked up straight the truck had a lot more power and didnt bog down as badly on a hill. It did at that time still make a thrashing noise and the check engine light flashed . Got up this morning and went to the Ford Store and bought a new FPDM and he put it on the truck ran worse than before now I have no power on straight road still hear thrashing sound{spark Knock} on heavy acceleration but it gets worse I pulled back in the garage and now it wont crank something else thats new is my gas hand has stopped working could my new OEM $500 fuel pump be bad? Any ideas as to why at the blink of an eye it wont crank?

kanga2311

If it was misfiring that badly, you might want to check all the plugs again. I know I sound like a broken record, but make sure you use di-electric grease when you put the cops back on. Check again for cracks in all the cop boots. Also, when it was misfiring, you could have damaged the cats. Before you check your plugs, disconnect the battery. After everything is done, reconnect battery, start truck (hopefully it starts now), turn off radio, turn off AC, let engine warm up, turn AC on (idle for 1 min), put foot on brake and put in drive for 1 Min, then go for at least a 10 mile drive. This relearns your fuel curve. But your best option might be to bring it to the dealership. It can be difficult to diagnose over the internet.

Masi1926

Or you could put new coils on and solve this.

av8roc

+2 on the coils but don't rule out injectors, they are known to stick open and cause a misfire. Also if your CEL was flashing while under load it is a misfire and raw fuel is being dumped into exhaust potentially damaging cats and even worse, internal engine damage (hydro-lock).