I took my '04 4X4 Screw 5.4L in to have the brake light seal replaced due to a leak and mentioned that I'd like to have TSB 04-21-14 done to the truck due to sluggish take-offs, etc..... Well, I got the truck back and can't tell any difference in throttle response, but man o man, my MPG has dropped by at least an average of 2! Can I disconnect the negative terminal on the batter for a certain period of time to reset it back to the original code?

Thanks,

Sackett

 

when did you have the pcm updated...your loss in mpg could be due to the computer having to re-adapt to the driving... if you give it a few cycles, it could level out again... someone else may have more info for ya-
good luck- jj

 

Sorry that you did not experience any performance gains. Made a big difference in my truck. I hope I did not lose to much on MPG. By the way, I see you are in Sugar Land. My daughter and her family live there, just off 59 at the western edge of town.

 

The only way to return to the previous flash is to have it reprogramed by the dealer.
As to training it back, assume that it will take at least a 100 miles. Check in the manual. The training proccess will involve letting the truck idle for a few minutes, and going through all phases of driving, including nailing it, and freeway running. Then after that, top it up, and test for miles per gallon.
Oh yeah, due to the flat shape of these tanks, don't try to test mileage on 1-5 gallon fill ups. Let the tank get a little bit down, half tank or lower for real figures.
Hope it works out,
Chris