My 04 FX4 just doesn't have the throttle response I would like. I've cleaned the TB and the MAF. Would changing the plugs make any difference? If not what can I do?

 

Can you provide more detail? Such as is the truck lacking power, or is there any bucking or hesitation? What engine do you have? What maintenance have you done recently or in the past (i.e. fuel filter change, spark plug change, any modifications, etc).

 

It doesn't seem to so much lack power or hesitate it just seems like when I put my foot in the throttle i can go a long way before feeling anything, but like I said I wouldn't call it a hesitation where all of the sudden a power surge occurs. Its the 5.4, original plugs. The only mods I have done is the Gotts. I plan on checking the fuel filter this weekend.

 

Original plugs....what's the mileage on the truck? Original fuel filter as well?

There was a post some time back that described the proceedure to recalibrate the "drive by wire" pedal (formally known as a gas pedal) to remove any free type play. It had to do with turning the key to on (engine not running), then pressing the pedal down to the floor, releasing, doing it again, releasing. Then turn the key off.

Search on this. It too is a free try. Maybe your throttle body is out of adjustment and this proceedure will get rid of that pedal lag. Worth a try before you go out and spend money on a plug replacement. A 2004 5.4 has the spark plug breakage issue, so you won't be a happy camper if/when the plugs are changed!

 

I know the plugs are original with 130k. I plan on changing them as soon as i work up the courage to do them myself or the money to have a mechanic do them. I don't know for certain but I'm guessing the fuel fliter is original too.

I will check for the drive by wire thread. Its free so its worth a shot in my book!
Thanks.

 

run some Sea foam thru that truck will help clean it out and will also help when changing the spark plugs

 

You definitely need to change plugs and fuel filter. Hard to diagnose your problem with so many worn out parts. Check or change air filter, too. You could/should clean your MAF sensor (with MAF cleaner or electronics cleaner). Seafoam your intake and you'll probably notice a big difference, too.

 

Already ran half a can through on my last fill up. I plan on doing the brake boost line technique with the rest.

Also would a reflash possibly help the throttle response. I was doing some searching on old threads for this and ran across that as a suggestion. If so can I just call the dealer up and ask them if I can bring it in for PCM update or will they charge me for it?

 

I like the way its setup myself. Seems they offer more progressive acceleration this way. For example a GM truck you have no progression from half to 3/4throttle. It seems faster this way but really its not. Smoother throttle means smoother truck which is a blessing when off roading or towing.

 

I would most definitely get the plugs changed! I've got an 06 with 95k that was a little slow on throttle response, had my plugs changed and really woke her up. Mechanic showed them to me, can't believe the truck ran at all. He also changed fuel filter.