My truck's giving me a consistent 16 on the fwy and 14-15 around town, empty ... this is disgusting! I recently replaced the VP and thought that fuel mileage would have got better ... not!

Stock, I was seeing the same economy, so my mods have not made a difference.

Has anyone changed out their MAP sensor, without symptoms, and seen better mileage? I recently cleaned the IAT. Didn't really need it and showed no increase in economy.

I know I've got 410's, but this is ridiculous. Any input?

BTW: At what temperature should your grid heaters begin to cycle? I live in So. Cal. and mine religiously cycle every morning. Is this a sign the IAT is shot?

 

Sounds like what I get. Drive slower, I drive 55-60 with 410's and see 19-21 unloaded. At stop lights is were the fuel goes. Accelerating slowy really helps city.

 

Below 60*f they cycle.

 

I drive a moderate 60-65 on the fwy, drive the speed limit around town, I accelerate slowly, I rarely ever exceed 2000rpm, I keep my shifts between 1900 and 2000 ... what more can I do????

 

I average around 15mpg. I have tried cleaning the IAT, searching for boost leaks, cleaning the air filter, and changing the fuel filter. Same oh same oh. I have been dissipointed for a while now. I here of folks getting around 19mpg with the same set up as mine. What the heck? I drive slow keeping the RPM's below 2K.

 

Fellas, I got the same problem. Got the frickin 4:10 rear. I got 33's on her now, BHAF and 5 inch straight pipe. Calculated my MPG the other day when I fueled up, it was only like 15.65 MPG!! , A buddy of mine told me about Diesel Clean (i thin thats what it's called). It's a white bottle with a red top (also sell the silver bottle which contains cetane boost) and this is supposed to be great for cleaning your injectors and is supposed to increade MPG by 8% We'll see what happens.

But I think the problem is that straight pipe sound is too beautiful and i just cant keep my size 12 off the go pedal!!

 

At least you've got an excuse for you poor mileage. Nothing I do helps, that's why I'm thinking it's maybe a sensor.

 

tires really kill milage.. i saw a 2mpg drop going from 235 wides to 285 wides.. i think they were 235/85/16 to 285/75/16 ? Even after size correction still down 2mpg after changing tires.

surely can imaging that milage with 33's knowing i dropped to 16mpg from 18mpg city driving just changing to bigger tires.

 

That is Power Service Diesel Kleen. The silver bottle is the summer formula and has a tad bit more cetane booster in it. The white bottle is the winter mix that has the anti-gel additive and a little less cetane boost than the summer stuff.

 

I have 265's, which I don't consider overkill from the stock 245's. If I could pick up a couple of MPG's I'd be happy!

 

I get 15-16 around town and 16-17 hwy the 410 really hurt and my 4 wheel drive also my dad has 2 wheel and 355 and get 19 and 22 hwy I put 35 on my truck but didnt help much I went up about .3 miles to the gallon

 

I wish the manufacturers would release perhaps a LT 275-80-16 for us. A little wider and taller than stock. Something to fill up the wheelwell but not a mileage killer.

 

I believe the 255-85-16 are the way to go. They're hard to find in E but they are available in D. The D's are rated at 3,000lbs where an E is rated at 3042lbs in a stock 245 ... can't get much closer.

Edit: Maybe the 235-85-16's would be a better choice. E rated and a hair under 32". Tread width is narrow at almost 9.5", which should add to fuel economy.

 

I'm in the same boat. I run syn in the front and rear diff, in the engine, but never got much over 15 mpg, after purchasing the Smarty I'm getting 17.3 mpg around town and that's on the s/w7.
It's the only thing thats helped my mpg's other than Blue Hair Speeds.