I have an 01 super duty with the 5.4 and as of lately it seems like it has no power and really sucks the gas.It has 129k on it.any suggestions on how to bring it back to life? Thanks

 

Unless it's been abused-129K miles is really just getting good and started with a modular. I'd say check spark plugs and replace if they're over 30K miles or so,and clean the MAF sensor.At that mileage-it's also possible that the primary "light off" cats are bad or clogged,and need to be replaced.
JL

 

Sounds just like my F-150 I just traded in.

OK, does the engine seem to lay down when you press on the gas? Does it seem to start OK but as you accelerate the power just isn't there?

If so, you're catalytic converter is probably clogged. To check, disconnect your exhaust at the Y pipe and take your truck for a (LOUD) spin. If she runs good, you've found your problem.

 

Oh....one other thing.

Welcome to FTE!

 

it starts fine but when you accelerate it just aint there.It will have to downshift at most hills and pulling an empty landscape trailer felt more like a semi trailer.At 90k it had good power but it just goes down from here.

 

Have you ever changed the spark plugs? I purchased my '98 model with 107K miles on it,and on the test drive it was weak,and would stutter under heavy throttle.Changed the spark plugs(they were the originals),and it ran great after that.Honestly I dunno how it was running before I changed them-there was a .080" gap or more on every plug.
JL

 

Spark plugs, air filter, fuel filter, PCV valve and clean the MAF. These should surely help.

 

I just cleaned the MAF,new air filter,and checked the PCV valve and there is vacuum.Would it be necessary to change the plug boots or just the plugs and how hard is it to change the fuel filter on one of these?Thanks alot.

 

while you're at it (or your mechanic) I'd change the spark plug boots.

 

Older gen motors will do 300k miles, and I would not expect anyless of the modulars. Like LX said, clean and tune up. I'll add do o2 sensors and fuel filter, and run some high test or seafoam to clean up the topside.