Engine/Transmission (1998.5 - 2002) weak engine, help

[KSommer]

not my own truck, so i'll do the best i can...

2001 2wd one ton, six speed, 3. 55 rear gears.

my friend bought this truck about one year ago with 126k on it and a goosneck ball in the bed. this summer he loads two jeeps on a 25' heavy equipment trailer and heads out to CO for a week. averages only 10 mpg, can't pull up any hills unless he downshifts. basicaly the engine would not make any power under 2,200 rpm. where do we start? he has done all the normal maintenance, the truck gets 20 mpg empty.

his '93 would pull this load all day and get 14-16 mpg.

thanks for any help...

kent

 

[FourBarR]

you didnt mention gauges ,so i assume your friend doesnt. you need to check the lift pump fuel pressure. should be 12 to 15 at idle, at least 6 to 8 at wot. next check for leaks at the hoses between the turbo and intake . these have a habit of leaking. on stock truck boost should be 20 t0 22 in. forgot to mention the fuel filter, make sure its not plugged. check the air cleaner element . does it make smoke when pulling ,what color ?hop[e this is some help, come back and let us know what you find.