My engine runs 60mph@2000rpm, and 70 mph@2500rpm.
Is this too many rpm's?
I am getting 12mpg city/15 mpg highway.
Is there a way to modify through ecm setup for lower rpm's ?
Tires are 265/70R16. Stock suspension and all.

Thats about the same RPM's mine is running at those speeds with LT265/75/16 and 6.0 2500HD CC 4.10 Rear end.

Can I Lower This For The Long Run..?
I Mean, Can I Modify This Through Reprogramming Ecm?

You may can modify your RPM's with a performance tune.

My engine runs 60mph@2000rpm, and 70 mph@2500rpm.
Is this too many rpm's?
I am getting 12mpg city/15 mpg highway.
Is there a way to modify through ecm setup for lower rpm's ?
Tires are 265/70R16. Stock suspension and all.

the rpms are too high 2000/2100 at 70mph is normal...the question i have is why.....70r16 tire sounds small especially for hd....larger tires lower rpms....a 75 tire is proper...not 70

Thanks, I Appreciate The Feedback. Also, Is There An "hd" Only Forum?

Thanks, I Appreciate The Feedback. Also, Is There An "hd" Only Forum?

not to my knowledge... but if you search you will find hd is not much different when troubleshooting vehicle failures....this forum is very good for info ...

That is so true, regarding the failures. Besides, platforms are quite similar except for special/hd only features.
I will try to go from 70's to 75's. I know this will reduce rpm's, as well as everything else related to tire revolutions...
Maybe this will even make my MPG's look better in numbers at least, don't you think?