Albertko

I have a 2008 dodge ram 2500 6.7l. The problem is that I used to get 17 mpg about 6 months ago but, now I'm getting 11.9-12 mpg. What could be the problem? Also, one other problem is that occasionally when I stop at a red light and after i press the gas pedal the truck drives very slow and shakes very bad it does this for the first few seconds or sometimes minutes and then something seems to clear up and it actually starts to drive. Maybe someone knows what could be the problem here and maybe the mpg problem comes from this.
Please let me know if you have any suggestions.

xcc_rider

Could we have a bit more info? Any mods? Any recent mods? What is your maintenance history? Have you religiously changed your filters? Have you had any codes\cels? Have you checked for pending codes? Any gauges like rail and boost pressure?
And anything else you can think of...

Albertko

This is a stock model truck so no mods. I changed a fuel filter, put a k&n air filter, cleaned EGR valve, and oil change with new filter. The check engine light comes on every now and then but, turns off by itself.

xcc_rider

Well, an intermittent cel is a good clue. Go have the codes pulled. Look for pending and inactive codes.
If you don't find any then the next time you get the cel go have them pulled.

BigIron70

MAF sensor or MAP sensor dirty, possible injector issue. I would try cleaning sensors and then try some injector cleaner first. Remove and clean O2 sensors use compressed air only to clean and put some anti-seize on threads. What codes are setting would help with diag. your truck.

Rudy Del Pardo

your injectors are clogged up. just throw some atv fluid in your gas tank and you will get your mileage back