Check your oil level. If too high, you could have a failing Injector(s), and your oil will smell of diesel. If not, give it a good healthy dose of injector cleaner, and run the hell out of it......see what that does for you.

 

Thanks, I hope something works

 

Easy test to check if there is diesel in your oil is just pull your dipstick out and let the oil drip onto a piece of paper and the diesel will separate from the oil and leave a much lighter color ring around the oil.

 

Has anyone had any sensor go bad or act up and cause a drop in milage lime this?

 

a very dirty IAT sensor would cause your fuel mileage to plummet. On your 03, I believe its located just aft of the air filter box. In fact it should be attached to the lid of the stock air filter box. Its held in place by 2 small torx screws, and has a 2-prong electrical connector. Try cleaning it, carefully with a q-tip and rubbing alcohol. If your using an oil type air filter, the IAT will become covered in oil residue and fine dust, hampering its effectiveness. Give that a try. Also, check your tire pressure. Have you given any thought to wearing/ worn wheel bearings, extremely dirty brake calipers preventing your brake pad(s) from receding and causing it/ them to drag abit on the rotor(s)? How about a slipping trans or converter? Just thinking outside of the box......

 

I believe I do have an excessive amount of brake dust showing on my rims but the truck coasts fine and just once in a blue moon if I let off the throttle and let go of the wheel it will pull just ever so slightly to the right, the pads are new from when I bought the truck, I chalked it up as shitty pads the dealer put on, since they've squeaked since I got the truck

 

You may have a sticking caliper, or your alignment is off a bit. I have high quality pads on my rig, and they squeak so bad its embarrassing, but they work well. Other than what I posted earlier, im pretty much stumped.

 

Does it make any difference with the tuner off or on? I wonder if the tuner could be not working.

 

Clean your sensor By your air filter. Check your Rail pressure sensor on the rail. No codes no smoke.... has to be your tuner or your right foot!

 

Did you ever get that issue figured out???