I went on a trip the other day about 900 mi w/ about 7000# in my mirror. 100mi, in my tps wire melted and grounded out on the exhaust brake and put me into limp mode, but I got that fixed and kept going, but I noticed that on the interstate the fuel mileage would drop from 13.5 to 11 when I put the cruse on. This is about 80mph on the interstate. When I got onto a secondary road and went 70 I was getting 8mph to 9mph. Whe I speed up from 70 to 80 my mileage will raise but when i put the cruse on it will drop again. Has anyone noticed this in their truck, I never did until i had the problem w/ the tps. I took the truck in an they cleared the codes but said they had know idea about the fuel mileage thing. The faster i go the better the mileage until I put the cruse on. 70mph is 8 to 9 reguardless if the cruse is on or not 13.5 at 80 w/ cruse off and 11 with the cruse on. any ideas!

 

What level are you running your Six gun at
Are you going by hand calculations or the overhead gauge
It's been said with any type of chip installed the overhead will be off due to the fact that the computer does not actually calcualte mpg but goes by throttle posit, fuel pressure, and a host of toher things

 

I run the six gun on 6 most of the time. I have taken the mileage by hand and it is about .5 from the overhead reading. I have not penciled it out with the cruse prob but i will this weekend and find out. thanks

 

Ok, next question is why are you running with the Six Gun on level 6
Try running with the SIx Gun in level 3, that's is where Banks says you will get the best mileage. They also say you should not be running in level six except for short duration you should be running level 4 or less

 

Local601,

I could consistently get better mileage with my foot than with cruise control in my previous truck. (I haven't towed with the new one yet, but I'll bet it's the same way.) I think it's because the cruise control insists on speeding up on every overpass and hill where I would just hold steady throttle position and let speed bleed on the uphills and catch up on the downhills. Steady throttle is more efficient than steady speed. I wish I could buy a steady throttle cruise control unit! Anyone?

With regard to speed, that could have to do with two things. Most likely it is that the efficiency of your engine/fueling system is at its best at the RPM required for that higher speed. There is also the possibility that the airflow over your windshield at higher speed directed more air over/around your trailer than at the lower speed. I've noticed that sometimes I was able to maintain higher speeds more easily than lower ones when it came to pulling hills. On that truck there was more power at higher RPM, which would make it easier to pull the hills without burying the pedal in the floor. Stepping to the floor is a good way to burn a lot of fuel, so fast or slow the average mpg I got didn't vary much. 9-10 mpg w/12' tandem wells cargo box.

HTH