So I was averaging about 13-15 mpg in the summer. Not so bad. Then I averaged 10.5 pulling 4,000lbs on a open car hauler. Not so Bad. But now im getting 11 empty? I guess I will be replacing my fuel filter and air cleaner soon. Anything else im missing?

Well you could do the mods i have and get about 10 mpg empty.... (i have a heavy foot)

My '94 blazer is nearly the same truck as your '95 Yukon, and its not doing as good as I would like lately either, used to be 500+ Miles per tank (16-18mpg) now its a stretch to get 400 (12-13mpg). The cold weather calls for longer idle times to warm up, and more 4wd usage, and that hasn't helped things much...

I average 16 to 18 on a 2000,3500 pickup with 410 rear gears. Keeping the fuel filter changed regular as well as the ari cleaner makes a difference. Also use an injector cleaner in your fuel helps to keep things running well. I drop off about 50 mile per fill up during the winter beacuse of the longer warm up times and 4wd useage.

Not to mention "winter blend" is a slightly less peppy-er tank cocktail = less mpg

Winter blend fuel really kills the milage. It is the same for everyone. It is very common to see a 2 mpg drop in milage this time of year.

I had a guy at a station admit to me once that they blended their fuel 50/50 with kerosene in the winter time...haven't bought fuel there since. Even though I run conditioner every tank, doesn't make up for the aeromatics and parrafins that kerosene lacks.

I was told to add a quart of engine oil to my diesel tank at every fillup to increase the cetane rating of the fuel. Didn't believe it but one day I was filling up and was prowling in my tool box waiting on the hose to shut off and found a quart of oil so I poured it in with the diesel and my power seemed to be better and the mileage went up 1 1/2 miles per gallon. I pour it in every time I can now. May have been a freak deal but it seems to have worked for me.

I had a guy at a station admit to me once that they blended their fuel 50/50 with kerosene in the winter time...haven't bought fuel there since. Even though I run conditioner every tank, doesn't make up for the aeromatics and parrafins that kerosene lacks.The hottest diesel fuel is that which is made from refined parrifins and waxes which have something like 240+carbons. I've read the only fuel that has a higher than 100 cetane is refined from this denser hydrcarbon.

The aeromatics are lighter oil molecules 9-16 C, hence the aero- they ready diperse into the atmosphere becoming airbone particulates.

kero has more distilate in it (like mineral spirits)

The denser the fuel, the more power per gallon. They blend it weak because with modern reformers they can streatch "diesel" into gasoline and back again. That and the heavy stuff will turn solid under 40F

You guys ever read the studies on what diesl exhaust does to you after breathing soot particulates? It's as heavy in the lungs as any particle, like asbestos or coal dust.

Something's not right. My '95 tahoe gets 16 winter and 18/19 summer pretty consistently running my 265s at 60 to 65 PSI. I also use Power Services in every tank. Have you checked your tire pressure?

i get 17 in the summer and 14 in the winter with 265's at 45 psi. all of my driving is on the highway going 65-70 mph. that is what hurts my mileage.

i try to use power service or something else at every tank. i would never dump motor oil or automatic transmission fluid into a fuel tank no matter what somebody says. that cant be good on the injection system.

i had never heard that before about soot in the lungs. but at least diesel fumes wont kill you in a confined space like gas fumes will.

I add Mystery Oil at every fill up. Not sure if really does anything, but the truck seems to run a little smoother.

Ive been adding about 3-4 glugs of power service Diesel Kleen +Cetane Boost at every fillup. Never noticed any difference when I ran out and didnt have any. Now im driving around like grandma trying to 30gal/week.

I add Mystery Oil at every fill up. Not sure if really does anything, but the truck seems to run a little smoother.What does that smell like when you pour it? I always thought it was kero.

Does it have a cadaletic converter? Possibliy plugged