I have 06 6 speed. The truck seems to hesitate and not have power at lower rpm. It is intermittant and worse when the truck is cold. I just did a trans fluid, tranfer fluid and pumpkin oil change. All levels are fine but now this. How can I tell if the lift pump is bad? oh, and fresh fuel and fuel filter.

 

I used to have a big puff of black smoke and plenty of power when i mashed the throttle. now I don't. any ideas?

 

Have any guages? Fuel pressure would be a perfect thing to know right now! How many miles?

 

No guages, I have about 39,000 I've put on since Dec.

 

Hard to tell w/o a FP gauge.