Lack of power & MPG

[Swingblade6]

Aloha everyone. I'm new to diesels & this board. Need advice (long)

Recently purchased '01 7.3 f250 4X4 cc w/68k miles & am very dissappointed in both towing power & fuel economy and would appreciate some input. Not sure of true weight but boat & trailer prbly are in the 8.5k# - 11k# range depending on fuel, gear etc. Truck did not have gauges but have ordered a pillar mount pyro, tranny, boost set up. I have changed oil & filter (full synthetic), checked trans fluid (ok), chnged fuel filter, added Diesel Kleen to full tank of fuel, airraid intake (filter is acceptable, ordering new one - feed tube clean). Haven't checked the turbo yet but will, don't think thats the prblm since no white smoke or hesitations and it spools fine.

Truck is chipped but don't know with what. 8-10" lift running Toyo 38's. Custom front susp' with coil over shocks, airride rear, rear hitch. Oversized transmission pan & rear diff' cover. Thank God for a custom 55gal tank. Other than fuel mileage & towing on grades truck runs strong with no smoke, hesitation, or other signs of a prblm.

Driving painfully conservative at all points (I mean that - I am 50 yrs old), Fwy mileage MAYBE 15 / intown 13 / towing 9. Towing 6% grades brought me down to 35miles hr & slight grades to 55-60 (I am not flooring it but close enough). Truck seems to not want to downshift unless I forced it to even in tow mode. From what I've read on here that is far below acceptable. Have friend with similar set up (truck, lift, tires etc - no chip but only 25k miles) 2006-6.0 who pulled the boat to mexico - he breezed those grades at 75-80mph & altho I don't know his actual fuel economy he says didn't drop it much off unloaded.

My reading here leads me to believe it's the stock gearing with the 38 tires. Stating that my biggest priorities are towing power & then fuel mileage, am I on track here? If that's so what gearing recommended for daily in town use & towing? Best online source for such gearing front & rear? Any other suggestions? Any qualified assistance is much appreciated. P.S. best place to buy rear stabalizer?

[stroker27]

Originally Posted by Swingblade6

Fwy mileage MAYBE 15 / intown 13 / towing 9.

welcome to the org. and welcome to the world of big honkin trucks not getting 30 MPG im joking.... someone will help you out soon, my truck gets about that mileage but tows great even on grades, but I dont have a 10 inch lift. i think youll find that most people realistically get 15-17 in their trucks, so your prob OK as far as Problems With Your Truck go. as for the no power. theres plenty of people that will help you out with that... get yourself on over to the introduction forum and put up some stats so everyone can help you out!

[HillBillyDelux555]

I was going to say the air filter but you have an aftermarket kit. Could be the gears and is the tranny stock? Stock tranny w/ a lift and 38 tires does not mix when towing.You might want to figure out what chip is on it and see if it is recommended for towing. If it is the tranny an you want to get a new, better one I would recommend Brians Truck Shop, its in Lead Hill, Arkansas. Hope this helped and good luck w/ your truck!!
Ohh yea

[CHAD5.0]

I would definately say the big tires with stock gears ars causing major power loss, especially towing that much weight. I know some of the gear manufacturers have a formula to figure what gear you need with different size tires to get you where you want to be.

[Swingblade6]

If it is the stock gearing w/the oversized tires then why did my friends stock 6.0 with same tires & stock rear end pull same load and grades easily at 75+ while I bogged to 35? (yes I am calculating for tire size) Is the 6.0 really that superior of an engine? And let's not forget my tranny not downshifting unless I force it to.