Over the last few months I have notice a obvious decrease in MPG's that my truck is getting. Unloaded, in the summer I used to be able to get 17-18 mpg's. Loaded I would get 12-13mpg. I recently threw the code P04040 which I believe is a the EGRV saying the EGR valve is not matching its commanded position. I am running Spartan Tuning, and 250hp and up it shuts the valve off, but I am getting the code when I am running the 210, which enables EGRV function. I am now getting pretty terrible MPG, roughly 11-12 unloaded and 10mpg loaded. Is it possible that it is stuck halfway open/closed and is causing me some problems? Or would this not have an effect on MPG's?

Thank you very much

 

Well all things point to bad ecomony due to excessive EGR so I would agree. I have asked a few people of you could take the cover off of the body and free it up. Some say yes maybe, others no.

Maybe run some injection cleaner thru there and see what that does.

 

Changed out the oil, the fuel filters and cleaned the air filter (although none of them needed to be changed) and.... no more sticking EGR, and an increase of MPG. It was strange, after I must have got some bad fuel and the drain water light came on soon after came the egr code. I am not sure how the two are directly related, but who knows. Thanks for the help Senix.