I got 19.6 MPG from Seattle to LA.....

But that was 55-60 MPH, with easy slow starts and cruise control locked the whole highway.

 

Yes it is caliberated, I have it pretty close to being correct. The wheels and tires are heavier but not that much more than the stock 20's


Oh well it just seems I could be getting better

 

Just a guess but I would bet you lost some low end compression performance thru your exhaust mods. Performance wise straight thru's usually gain hp at WOT but loose low end performance. Your truck may be less efficient climbing hills also because of this?
Your exhaust and cai may be working against you and those hills also.
Anything over 70 mph on the highway is also going to put you under 16mpg.
Subtract more for hills.
Good luck.

Not normal... Do you either have a lead foot or frequently drive in a hilly areas?

I average 14-15mpg around town and 17-19mpg highway and even better on long trips.

 

i was thinking about putting my stock intake back on for awhile but then of course i cant use the gryphon

but i can see if it helps any

 

you don't have a stock performance setting?
If you change anything burn a tank or 2 of gas so the computer relearns changes.
I have read that disconnecting the battery is no better than just driving with changes since the truck has to learn anyway.

 

dont believe i do

i think i only have 89 performance, 89 towing and 91 performance

 

So you are saying that all your tunes are for the cai and exhaust setup only?

 

that is what im saying

 

Stock is worth a try to see what you got... but you still will not really be stock if you take off the Cai and tuner....you really need a few dyno runs unless you just like the sound better than the mileage.
Good luck.
Everything has a price...