Sorry for not posting the problem. Someone was stealing diesel from my tanks. I thought this was the case but was not sure until I went to get in my Truck one morning and noticed fuel spilled on my chrome tanks, which I had just cleaned up the night before.

They were getting 15 to 25 gal at a time, and not leaving any sign of them getting it until they must have almost got caught and had to leave in a hurry.

Got Locking caps, and have not had a problem since then. My fuel mileage is at 5.2 mpg. I thought it was close to 6 mpg, but was not doing my math right. Can't really complain about 5.2, as most of my loads TGW is 88,000 to 95,000 and running hills.

Originally Posted by Papa Rick:
Got Locking caps, and have not had a problem since then.

With diesel prices what they are, everyone should invest in a set of locking caps. Cheap insurance.

Strongly suggest you have the charge air cooler pressure tested. Mine went bad once with just this result. Test is quite simple and cheap, should be done yearly. Hope this helps

I had to put my truck to a cat. dealer in N.J. , tomorrow I gonna get the analyzis! I will post you guys the test!

Liquid gold!!

If the only difference you notices was on a 300+ mile trip, it aint that bad.

I came back from Spokane,WA last week with 4.9, all the way to Allentown,PA...I had wind up my a$$ the whole time running 43K load.

You are fine..

I got my truck back but nothing changed because in N.J. I-95 exit 13A at CAT. did nothing and they tried to charge 2 hours labor!
- My truck sometimes loosing power-mostly not.
- Increased black exhaust when I going up hill-sometimes go up 25 mph when lost power! Sometimes on same hill running up strong, no problem!
Any advise! Thanks

How much to replace or repair the turbo on 2002, C-15?
Thanks

Finally : the water separeter was the problem!! 500 $

air getting in?