Ive had my injectors out a few times recently, they're usualy prety dirty on the tips, carbon build up and such. The truck always seems to run better for a day or two after i take them out and clean them off.

 

Mine has way more than a haze at idle and slow driving, i usually get reasonable milage though. I sent off my original injectors to get rebuilt, fopefully that helps it out.

 

I've gotten 21+ mpg highway with mine, usually between 16-19 because half of my daily trip is dirt road. I havent seen any fuel leaks, so i dont know what the deal is with the 7mpg.

 

Check your fuel filter for bad stuff. When you take it off, make sure you drain it into a glass or something so you can see what comes out of it.

Try adjusting your smoke screw, on top of the AFC housing. Check the Sticky for the how-to.

Check your air filter, and back-clean your radiator/IC/condensor. All that dust from the dirt road will plug up those cooling fins faster than you think. Oh, check your tire pressures too.

All this still doesn't add up to such a huge overnight drop in mpg's though. I'm stumped as to what it could be... Unless one of your friends snuck about 20,000 lb's worth of weight in your bed?! Even then...

 

What type of pressure are you seeing going into the IP?

Also have you check if any of your brakes are hanging up?

 

I'll chech my fuel filter, its pretty new but yea something could have gotten stirred up in the fuel tank or something. i washed my air filter not too long ago and it dont look that dirty, might clean it again if i dont figure nothing out. Tires might need checked. The smoke screw should be at stock, the IP has been rebuilt twice in the last couple years and is still under warrenty(dont want to void it), plus the smoke this thing puts out is whitish blue. No black. I'll check all this stuff when i get time to, thanks.

 

Timing? Haven't read the entire thread yet, but, fuel pressure?

 

I dont have a fuel pressure guage yet. I do plan on getting one though. Something does seem to cause a "drag" on my truck sometimes, the brakes never get hot or nuthin. Ive gotten fairly good milage with it doin that before though. What ever does drag sometimes did drop my milage about 3mpg. (down to about 16 vs 19-20mpg+ on the same all highway trip). Never down to 7mpg though lol.

 

Im actually REALLY suspicous about the pump timing. Externally the pump is lined up on the timing marks, i havent ever looked at the timing gears though, but im starting to wonder if maybe the timing inside the pump got messed up all of a sudden. I dont have a fuel pressure guage yet, i do plan on getting one soon though.

 

Who installed the pump? Was it a repair shop that did the work?

With a relatively new IP I'm thinking you're getting a problem with the injectors somehow since oyu're hazing pretty good at idle. You may also want to check your turbo to make sure it's spinning freely.

I don't remember if you said auto or bolt action. If it's an auto you may have a transmission problem such as a torque converter slipping or something. If it's a 'Rag maybe the clutch is shot or dragging.

Lastly, pull your front wheels and see if they spin freely and don't make noise. You may have a hub or bearing problem creating drag. While you're tinkering around check the fluid levels in both pumpkins.

 

Mines a "bolt action". I thought i filled out my sig, I'll get on that. Injectors arent that old, and my original injectors will be back from the rebuild shop in a couple weeks hopefully, maybe that will help. See, the drag dont happen all the time. Theres a noticeably difference when it does it though. Feels like the brakes, but id think they'd get hot but they dont really. Last i checked the turbo felt ok. Yea a repair shop installed the IP. I checked the pumpkins recently and they were both good on fluid.

 

I've got to guess hubs if it's a 4x4 or bearings if it's a 2wd. Or, maybe, a dragging parking brake.

 

Its 4x4. Ok, i'll jack up the front and take a look at the hubs. Im thinkin its more of a fuel or timing related issue causing the bad mpg, but fixin the drag will help it im sure. Oh yea, turns out i did fill out my signature a long time ago, it aint showing for some reason.

 

Make sure the **** on the hubs turn freely and completely unlock (you'll know if you try to turn the wheel and it won't.)

I think you may have a combination of something in the drivetrain dragging as well as a fueling issue. You may want to go back to the shop and tell them your truck is running like garbage and you want to make sure it's not a problem with the work they did.

 

Ok I'll take a look at them. I check the front drive shaft some times when i notice the drag and it free spins. But maybe the transfer case is kinda catching when theres pressure applied from the engine??? Only when im goin down the road.