I don't know why but lately my fuel mileage has been terrible. On the same trip that I usually get about 20mpg I am now getting about 16mpg or under. The only think I could think of that would cause this is a bad injector or two, because I just recently changed the oil, filter, fuel fitler, and air fillter hoping that this would help.

So my question is will injectors that are going bad cause poor fuel milage? Also I have noticed when I start the truck in the mornings even though it isn't that cold (~40 deg) it will still smoke, and I don't remember it doing this when it was new.

Thanks

You don't state where you live, but I am guessing that the winter blend fuel is what is causing the mileage drop. Nothing new, everyone here in cold climates suffers the fuel drop every winter. 2-3 mpg is normal, 4 maybe on the high side. In the winter the trucks don't warm up as quick and burn fuel as efficient as in the summer, add to that extended idle times that you let it warm up in the morning.

I have same problem i do about 280 miles on 24 gal of diesel, whats the problem? thats big drop from about 400 miles on 24 gal, is that really due to a winter season or something wroing with the truck?

Also instead of running the winter front I put card board in front of the radiator. This helps it warm up much better, but could it be blocking off too much air? Because I almost have the whole radiator covered. Could it be getting worse mpg by blocking the intercooler too much?

And it isn't from letting it idle in the mornings. I now plug it in at nights which doesn't require as much idle time, and the trip is basically a one day trip up the the mountains and back. It is to the same location as last year, but I could almost always get atleast 20mpg or better.

I have my truck almost 3 years and have never seen 20mpg. Every fill up I reset the trip odometer and have gotten 19, but never 20. I would be careful putting cardboard on the radiator as it will give you hot spots. Better off using the cover or buying a custom winter cover.

20! Holy Cow! How do yo do that. I drove 330 miles yesterday on 18.3 gallons and that's my best ever.....

I didn't really think 20mpg traveling on the interstate was really that big of a deal. In the summer time I could get about 21ish. I always check using the trip odometer and gallons used on fill up, not just trusting the pickup to calculate it for me.

i too saw a drop in mileage when winter set in. i put on a winter grill insert and taped off the inlets in the bumper, and my mileage has come back up. suprisingly, the temp got up to 70 over the holidays and i was still able to keep the cover in place. the coolant never got any hotter than 200 and the tranny got up to 165.