So, im fairly new to truck modifications.. So please take it easy on me.

Im not a Fanboy of any particular make.. but i do have to say, I had a 07 5.3L Chev Silverado and it got much better gas mileage then my 08 5.4L F-150 and felt like it had more power to boot.

I am getting around 12.5 MPG on my truck .. it seems much worse then it should be. Today I installed a Hypertech Tune and a K&N Intake on it, hoping to do anything to it to make it slightly better on Fuel when i play nice, and give it a bit more power. Obviously I havent been able to calculate the MPG on it yet, it doesn't feel like it has all that much more power though. It defineatly sounds cool though.

My question is basically, the tuner asked If i wanted to modify the shift points, and the shift stiffness? Could I stand to gain power or fuel efficiency by changing the shift points? and Could somebody explain to me what exactly it means by shift stiffness?

My 07 5.3L Chev Silverado got around 17-21 MPG and Im getting 10-13 MPG on my 08 5.4L F-150.. with seamingly less power.. What gives? Does this sound wrong to you? Is there anything I should look at? I did buy this truck used so maybe there is something wrong with it, but I am missing what exactly it is... The rated MPG for the truck is 14-17.. and Im not even getting 14...

I realize Ive asked quite a few questions.. but any help on any of them would be much apprechiated