This has just started this past weekend out of no where.I went to accelerate up a hill and when it got to around 2500 rpms it just starts acting like a rev limiter kicks in.When i let off throttle it smooths out and runs fine, seems anytime its past quarter throttle it doesnt not want to move anywhere.If you drive normal in city conditions or on a nice flat round with barely any throttle it runs fine.I replaced the fuel filter no change, removed air filter no difference.Its actually at the shop now and they say its a transmission problem, my opinion i disagree fluid is up, no burning smell, and shifts fine under normal (slow) driving. please throw out some suggestions thank you

 

Have you found the problem

 

Sounds like a clogged catalytic converter.

 

Sounds like a coil ( or three) to me. Mine was doing the same thing. Had two bad coils.

 

sounds like bad cat to me also

 

x3 on the clogged CAT. Check codes and if you get P0420 (bank 1) or P0430 (bank 2) check for a leaky injector on the offending bank.

 

Sounds like the same problem i have, will not rev over 2500rpm at times. Spent $300 at dealer for them to tell me it needs new plugs. Havent changed them yet, probably will within the next couple weeks. Keep us posted

 

Disconnect the exhaust system in front of the Cat (or Cats if it is a 2005+ truck) and take the truck for a spin. If it is a bad Cat, you will immediately regain your lost power. If it isn't, you are not out any money.

 

Try checking exhaust flow out tailpipe(s)
If clogged enough to effect revving no flowproblem should be noticable at the tailpipe.

 

Cat converter , Just happened to me last weekend 700 miles from home pulling my car hauler full of four wheelers..

 

If you own a 5.4 litre ford with 150,000 miles or more change the intake manifold. It's plastic and has cracks all over it. It makes a world of difference. It's not that hard. It takes about 5 hours when it's your vehicle. Between the vacuum leaks and eventually coolant leaks it's worth it. Symptoms include loss of power, rough idle, misfire at speed, generally running like junk and eventual coolant leaks. I had egr codes, fuel pressure codes and temp problems. All were fixed with the intake manifold. I hope this helps someone.

 

That is the codes im geting and it feals like it falls on its face past half throttle do i need to replace them

 

It could be the cat but I doubt it. That damn intake manifold causes all kinds of codes to come up. The odb has no way to handle the problems it causes. If the injectors are leaking they can be cleaned. After the money I spent at the dealer diagnosing problems as they came up with nothing but codes that helped nothing. If it had not been for the coolant leak I never would have thought the manifold could cause that many problems. For the price of the manifold I would start there. You can get new orings for the injectors and replace them while doing the manifold. It's a good idea to do that anyway. It made such a huge difference. I wish I new this 1 year ago. Good luck.

 

Why spend money when checking the catalytic converter (as described above) is free?

 

Oh check it out for sure. Anything you can do to save a buck sounds good to me. The dealer told me my cat was bad and they wanted $1,200.00 to fix it. I blew it off because I didn't need an emissions inspection. Things kept getting worse.it was the manifold. Hope it helps.