'04 f150 4x4 screw. Stock everything besides a true dual muffler. 140k miles. This is my second f150 and it does not have the torque that my '02 had. Pulling a trailer is agonizing. Trans constantly shifts down to get up the slightest grade. I've sea foamed, cleaned the maf, new fuel filter. I'm thinking maybe new plugs are in order? Idles fine, engine runs good but it's like the truck has absolutely no ***** when it comes to pulling. Im not pulling anything too heavy either, just a 16ft trailer with light loads. Any suggestions folks?

 

what size engine 5.4 or 4.6. if its the 4.6 then yes, you are definitely going to have towing issues

 

5.4, sorry bout that

 

That seems a little weird for a 5.4. What gear ratio do you have in it? My 04 5.4 has 3.73s and it hauls like a stuck pig!

 

3.73- should be plenty. I don't understand

 

Tires are 325/60..... On there when I bought it. I know that this could hurt the torque a little bit but shouldn't affect it that much right?

 

It shouldn't be that drastic, because I'm running 275/65 tires on the stock 18s. Pulling our 20 foot tandem with 4-5000 lbs is a breeze for this truck, even going up the passes around here.

 

Well crap. I guess I'll try the plugs. Might need new coils too. Not sure if they are original or not. I would be surprised if they were

 

Post up how that works out. I have an 04 with similar mileage and notice it seems to be pulling less then it should, although I don't tow anything very often.

 

I also just thought of something. I don't know how long you've had the truck, but here's a story of what happened to this truck when my Pops was still running it. He took it in for a bit of a tune up, normally he'd do all that himself, but didn't have time for it then. The dealer finished everything my dad wanted done and part of that was a new fuel filter. Ran fine and everything, but a few days later he had it die on him a couple times. Started right back up, so he wasn't too concerned. Had to take the 20 footer north to pick up some stuff the next day and he noticed that it didn't seem to have as much power. He decided to take it to a different dealer and have them check it over. Turns out that when the fuel filter was replaced, somehow they wound up crimping the fuel line basically flat. Might be something to check out.