I was in texas working for over 2 months, didnt drive my truck much down, there but when i did i noticed fuel mileage was awful. saw on the diesel pumps that it was a 15% biodiesel blend. could that be affecting my mpg?
also, when going into 6th gear on some hills, un-loaded, the truck would bog down, and take forever to spool up. i havent seen any smoke at all though.
i'm wondering if my fuel filter needs changed? truck has 42k on it now. i dont know if it was changed prior to my purchase of the truck.
could the fuel filter be gummed up with the biodiesel blend? be the cause of poor fuel mileage and the slow spool up? i'm not getting any codes.
had some codes showing a few weeks ago, but i cleared them, unloaded the smarty and reinstalled it. haven't head an issue since.
any advice will be greatly appreciated.
thanks
kerry

 

The very first thing I would do is change the fuel filter and then see if that makes a difference. Id better even money it was never changed by the prior owner.

 

I agree to check filter..
Get some gauges for this truck would be very helpful for your trouble shooting when something does go wrong.. All of the following help greatly in determining what may be an iussue..

Fuel pressure
EGT
Transmission temp
boost

 

Change the filter. Remember that when you run bio or regular fuel that has a bio blend it will give the fuel system a little extra cleaning. If it still runs bad check for codes.

 

going to do the fuel filter today. I'll cut it apart and take a look. Let you guys know. If it's real nasty i'll post a couple pics.
As for gauges, they're on the list. Boost & Pyrometer. Dont think I need trans temp since I have a manual. Is fuel psi a mandatory one on the 67? I had one on my 01 5.9, didn't think I needed 1 on this truck since i'm not gonna hot rod it anymore than it is.

 

I was also in Tx for about 1 month, running that 15% bio fuel. My truck seems to like it, and gets decent milage with it.