My truck has never gotten the best of mileage, usually 450-500 miles per tank which hand figures to around 14-15. My last 4 tanks have really gotten bad. I pulled my 5ver back from Atlanta and got 211 miles and took 29.7 gallons. I know this is bad, but just figured it was from pulling 14k. My last 3 tanks have been running empty and I got 227 miles/28.6 gallons, 270 miles/29.3 gallons, and 256 miles/28.9 gallons. All three of these tanks were running empty not pulling anything! I cannot get 300 miles out of a tank. I don't drive hard and am not doing anything different than I have for the last 6 yrs I have owned it. Any suggestions?

 

I assume you've checked all the obvious things like the air filter, turbo boost clamps?

Do you have excessive smoke? Perhaps one of the injectors are going bad? How does it idle?

Let us know.

 

With such a tiny difference between those MPG figures, I'd have to ask... have you changed oil lately? Mine starts to go down when I get to the end of the oil change interval.

 

Sqrl, change your water/fuel seperator out first. Start with the basics first. Also, take off all the tuner stuff and see what happens. I have no tuners on my truck and I have gotten as high as 22mpg on my 4x4 Dually 6spd, but I have over time learned the computer to do this through low rpm driving.

 

Changed oil about 2k ago. Gonna change filters and clean air filter and run some fuel teatment and see if that helps.

 

What fuel treatment are you going to use?

 

Suggestions? Was thinking about seafoam.

 

I have never used Seafoam. I have used BG and Stanadyne and really didn't have much luck. I just bought Racor Conditioner Plus. Racor has cetane improver in it also. I have a diesel technician who uses Racor in his truck and really has noticed a difference in mpg and performance. I'll keep you posted.

Do you have any surge going on when driving or idling?

 

Let me add this about BG. I did use some stuff called BG 244 for diesel. 244 did something apparently because my fuel mpg dropped a few miles till the treatment ran through the system. 244 will remove the carbon deposits etc. On the flip side, I didn't notice a mpg gain when it returned back to my usual mpg beforehand though. You can try the stuff, but don't sh.t your britches on the price. I paid 44.00 for 1 quart and dumped the whole thing in the tank.

 

No running problems at all. I have run powerservice a few tanks and didn't noticed any difference, but it has been months ago.