Engine struggling? Please help

[Skylardog123]

Alright so before, i have complained about fuel mileage, but i have though of somethinf that might be tied into it, so before i got a custom tune and everything, the truck would do 100mph and shut off like every other truck, well i have since replaced plugs, wires, o2 sensors, knock sensors, fixed exhaust leak, and got an hp tuners custom tune, and several other tune up stuff, and the truck still only does around 100-103, and doesnt go much further, the governer is now set at 120, now i dont beat in the truck or drive it that fast at all, but wad curious what it could do after a tune, several other trucks get to 120 with ease without a governer, not sure why mine won't, only.has 165k miles, any help would be appreciated

[CamGTP]

Raising the limiter is one thing. Setting the calibration to not use the GMLAN settings in the tune is another. If the limiter settings were not switched from GMLAN to "calibration", it won't let you use the new set limiter. Without seeing the tune with my HP Tuners, I can't comment on how yours is setup.

 

I do highly suggest you stop going over 100mph if you are running the stock aluminum driveshaft. It was not designed to go above 100mph and do not be surprised if it explodes on you. Several threads and youtube video's of trucks chucking stock drivershafts when the rollers get way up there in speed.

[Skylardog123]

1 hour ago, CamGTP said:

Raising the limiter is one thing. Setting the calibration to not use the GMLAN settings in the tune is another. If the limiter settings were not switched from GMLAN to "calibration", it won't let you use the new set limiter. Without seeing the tune with my HP Tuners, I can't comment on how yours is setup.

 

I do highly suggest you stop going over 100mph if you are running the stock aluminum driveshaft. It was not designed to go above 100mph and do not be surprised if it explodes on you. Several threads and youtube video's of trucks chucking stock drivershafts when the rollers get way up there in speed.

I know the truck is running off the tune because i can go passed the 100 mark and truck doesnt shut off anymore