so i have a '07 lariat supercrew, 6.5 bed, 3.73 rear end. the issue is when i first got her 2 months ago i babied her, i go to launch hard n light up the tires and nothing. just a higher speed start. i ponder this for a couple of days. in that time i developed a vibration. i took her back to the dealer to balance the tires. they did a road force balance on it. on the way home she felt different, firmer if you will. i launched her hard and laid down a nice set of road stripes. she launches awesome for like 2 weeks and now she's back to the old garbage launch. i find it hard to believe that a tire balance helped her launch. what do you think could be the issue. the tranny isnt slipping, just not snapping like a 5.4l engine should. any help would be awesome. thanx in advance.

 

Reset your computer. THEN GO DRIVE IT LIKE YOU STOLE IT.

 

put some 4.10's

 

everytime your tires break loose it unbalances your tires

 

reset the ecm by pulling the neg terminal right? what does that have to do with the performance of the diff and/or the tranny?

i had a high spot on the one tire. i just cant figure out what was different from before the road force balance to after. the tires wont unbalance after you lite them up cuz the weights have not moved. even if they unbalanced i should still be able to lay stripes, but i cant.

4:10's will come when my 35" tires do.

 

the newer F150's computer learn as you drive. So as suggested, reset the computer. Then drive it hard and it will adapt to that. If you drive it like a Grandpa then it will act like that. I drive mine in a mixed mode, i take off hard some of the times, but drive the speed limit where ever im at. I get good launches when i want or need them.

 

The truck uses a drive by wire system (no throttle cable) so every time you puch it, it maybe diffrent. There are so many sensors that have to work, the only way to get consistant is probably with a custom tune or programmer. The stock computer is meant for every one and adjust to your driving habiats, so if you baby it and then all the sudden try to ride hard now it's gunna take a little time to adjust.

 

is there a sequence to reset the ecu or do i just do the old pop the battery wires? i get what your saying, but i just cant get my head around why in a matter of 8 hrs of balancing the characteristics of "the hulk" completely changed.

 

These trucks have a fly by wire set up. So it refers to the vehicle speed to move the vehicle. If it senses a possible slip it will upshift the gear. Causing the truck to gain traction. To fix that it would help to either re-gear the truck or install a programmer.

 

Don't feel too bad. I was never able to get mine lay a good ole #11. I had the 3.73's with the LSD rear (Heavy tow package) on my Lariat and it would not lite em up it you paid it.