I have a 2008 STX...4.6...6k miles
Certified pre-owned with 100k powertrain warranty.

Just got done with a 1200 mile trip with it and noticed something.

Between the speeds of 50 and 60, it doesn't like to accelerate, easily.

It kinda vibrates as you slightly press the gas, and is boggish. All of this is just under 2000 RPM's. If I hit the gas pretty good, it jumps over 2k RPM's and powers forward smoothly.

Releasing gas completely smooths the cruise, though slightly pressing the gas to maintain speed results in the sluggish response.

All other speeds around the 50-60 are very responsive and smooth.

Wonder if I'm over thinking/feeling this??? Definately doesn't seem right...

Thoughts?

 

Ive always found 4.6s to be a little bit on the sluggish side.

 

This is par for the course with these engines and the throttle setup on them. Mine actually started doing this again after I had a tune put on it so I had to have the tune adjusted. Stubborn engines.

 

ok....

Any other opinions?

Should I have the dealer check it?

Advice on "tuning" it?

 

Here is a good thread to check out some of the tuners..


https://www.f150forum.com/f7/tuner-programmers-9161/

 

After i bought my 4.6 i realized it wasn't ever going to be the beast i wanted it to be, so i decided to stick with the show mods. Eventually, when there is a bolt on supercharger i will defiantly buy it.

 

I have been told by a Mustang GT owner that the 4.6 develops its power at higher RPMs--3K-4K range. When I accelerate in my truck on the highway, it seems that a down-shift into 3rd and an RPM jump to over 3K is required to pass or speed up quickly. I am running a 3.55 rear end.

 

thanks for the replies.

I'm certainly not expecting the truck to be a beast, and don't intend on driving it hard.

It's just the low RPM vibration at those speeds is sort of uncomfortable and annoying.

I'll check out the tuners.

Any other options?

 

Actually I am having a similar issue with my 4.6 also. 50-65mph it shudders in the steering column, <50 or 65+ it is fine, just that mileage range.

 

ouch...mine doesn't shake anything...just a vibration you can feel in the motor through foot and seat...

Smoothes out the second gas is released.

errr....would have bought a 5.4 if this was a known negative.

oh well