Just got back from a 1,060 mile round tripper. Mileage was 14.79, 14.39, and 16.35 at 65-70mph with no chip and 4.10 gears. Temp was dead center on the gauge but has always ran like that since I replaced the t-stat, o-ring and neck. Checked the oil when I got home (still hot) and was between at least 1/2 to 1qt lower than the add mark and since I see no leaks I assume it's being burnt due to injectors(?), going to re-check when cooled off (no visiable smoke so I'm lost there). Truck ran great but do need some ideas on some issues. Do these trucks have a low fuel light? The piece of the radiator that the overflow tank hose connects to broke off and I just wedged a barbed splice in thats too small for the hose but worked ok aside from some spray at higher speeds - any way this can be fixed or do I just need a diffrent radiator? (I don't have the piece that broke off) The only other issue was hitting a deer about 7 miles from home causing me to have to pull my bumper out of my tire.

 

Were you towing anything? Those mileage numbers seem a bit low if you were truly saying under 70... I have the same gearing and tranny and I can hit 18-20mpg if I truly stay 65 mph on the highway...

I don't believe our trucks have a low fuel indicator... I always fill up with about an 1/8th of a tank left anyways...

 

Yeah on the last leg both tanks got to the needle being on the E and no light so I wasn't sure if it wasn't present or if mine wasn't working. I wasn't towing anything just had my normal load in the toolbox (~250#) and a few bags of clothes in the backseat. Only times I got over 70 were the 2 times I had to get out of the way of a semi (hit 85-90 both times) but they were for less than a mile. I belive my mileage is due to worn injectors, associated parts (o-rings, maybe computer or IDM issue), a sloppy tranny and no chip.

 

The chip isn't really going to net you a bunch of mpg... In my truck with stock injectors with 220k miles, I got a high of 21mpg one time...

It could be a bunch of things contributing to your lower fuel mileage...

 

Yeah its a down the road thing after a bunch of things. Right now I'm trying to decide if my truck has a slight miss or not since its been around 8 years since I've been around an OBS and can't tell if it's missing or if it's running normal and its just my imagination. Still in the process of fixing all that was neglected by the PO with the limited funds I have right now.

 

If you have over-sized tires, Did you figure that into your mileage?

 

My tires are 285s so a little oversize and no because I'm not sure how to do it and accoriding to my GPS my truck is only 1mph off so I figured everything had been adjusted to compensate (PO had 285s as well). If any one can explaine how to figure in the differnance I'm all ears but I don't think that my tire size will have as big of an impact as say 35s or 37s.

Got done cleaning it up and was just above the add mark on oil and of coarse low on coolant.

 

I usually keep mine just a hair over the full line with oil. My '96 had a low fuel light for the front tank but I never seen it come on for the year.

 

I usually just keep my oil in the hash marks when the motors cold (post chang filling) but accprding to my book it only holds 14 or 14.5 qts with filter and that dosen't reach the full mark on my dipstick.

 

It's roughly a 15qt system... I usually throw 1 qt in the filter, then 13-14qts in the case...