[GMAN]

Stowers Caterpillar on hwy 153 in Chattanooga has always been fair with me.

[GMAN]

I just thought of something, Fredog. When you check your fuel mileage to you rely on the computer or odometer?

[Heavy Duty]

Originally Posted by Fredog

well, my truck seems to have settled on about 5.3 miles to a gallon, it doesnt matter if I go 55 or 65 or 75, it gets about the same. Any suggestons on what I might do? I know I need to get it put on a computer but other than that, what should I do?
it's a C-15 cat says 435 on the tag, but I dont know if it's been turned up. has 13 speed and 3.55 rears.

Check the charge air cooler, if mileage doesn't improve at slower speeds it is probably leaking. Higher RPM's help it overcome the leakage. Cheap to check, I would do it first.

[Fredog]

Originally Posted by GMAN

I just thought of something, Fredog. When you check your fuel mileage to you rely on the computer or odometer?

strictly by the odometer

[Triple Digit Bob]

Originally Posted by Heavy Duty

Check the charge air cooler, if mileage doesn't improve at slower speeds it is probably leaking. Higher RPM's help it overcome the leakage. Cheap to check, I would do it first.

I try that with my truck. Still no work.

[Kranky]

Originally Posted by Heavy Duty

Check the charge air cooler

I'll second that.

[solo379]

Originally Posted by Kranky

I'll second that.

Yes, that where I'd start too....