superchips cause higher RPMs??

[s2gots]

So my '99 6.0 came with the superchips power programmer when I bought it a month or so ago....I removed the programming today because Im having other issues with stumpling RPMs at idle...I noticed after removing it that cruising at 70 mph on the highway the RPMs were almost 500 RPM LOWER than with the programm installed!!!! I was on the 87 tune, mostly to use for tranny shifts and larger tires. Whats up with that??? This should mean that I get better gas mileage!!!

[Green_Monster]

Did the programming you had on there have the wrong speedometer correction before you removed it?

 

I was just thinking that the reading might be messed up because of the tire size now.

 

It should be the other way around, but just thought I would throw my though in there.

 

Ben

[s2gots]

No, the speedo was accureate. I checked for the correct gear and tire size on the program after I purchased the truck.