So I have been hurting on my mileage for a long time, but with it being winter I have never really done to much to work on it.

I seem to have a black exhaust tip, I would guess either air or fuel problem as I have already done the plugs. I also did run some injector cleaner through. I just can guess that there is a mixture problem tho.

One thing I do notice is that mileage increases upon warmer weather. As in when the truck is sitting in the beating warm sun. It increases by about 3 MPG.

Any ideas? I have been thinking about intake maybe, but I don't want to spend the money unless I don't have to. OR NOT YET :P

 

Cold uses more power man, the added viscosity of the oil and the engine trying to compensate for the cold by running in open loop longer also helps the mileage plummet. Nothing to worry about really dude.

 

I've said it before and some may disagree but soot in the tailpipe IMO is related to running those factory Copper plugs (too hot). Since switching plugs (colder) I no longer worry or put much effort into shining the insides or edges off my exhaust tips. Reg use of FICleaneris helps especially in an older truck like mine or hemiguy's at plus 220 thousand kms.

I got my best ever mileage the other day on a 50 Km highway run at 120-130 KMH and hit a tad over 18MPG Imperial. But after a week of back and forth to work I am back to 22.8 L/100KM Avg after 200KM.

And during that run I noticed 15.1 MPG US reads 15.1 L/100Km on the overhead gauge when switching back and forth. Kinda like -40 meets -40.

 

I seen Bully-Dog, Hemi Right!

 

Everyone gets better mileage in the summer. The summer blend fuel burns more efficient since it doesnt have all the extra stuff in it to protect the gas from turning to sludge in the cold.

I've got black tips too. Thinkin about just paintin em black and callin it even lol

 

Seems like a hemi thing then haha...I realized it was going to work harder in the cold. I did fail to tell the temperature. Its only around 0 to 5 at that time, so I thought it was not really cold enough to make a 3 MPG difference? I would have guessed maybe 1 at that temperature. I could understand when its minus 20 or something.

Could it be the factory exhaust? That it just cant withstand all that carbon? Someone with a stainless tip or even an aluminum tip still have that problem?

 

my exhaust is 100% aftermarket from the longtube headers back. I have stainless tips and they're still black inside.

 

must just be a hemi thing...seems kinda odd to me, but i guess if lots of other people have the same problem then its nothing to worry about.

By the way how much of a performance gain did you get with your dual header back? I want to put in an exhaust eventually (stereo goes in first) I however do NOT want to be like all the people around here do and just put their exhaust into a Y and call it a dual exhaust! How much extra work is there into pulling them from the header back instead of a cat back?