I was wondering what I could expect for mpg's on a 97 2500 7.4litre 4x4 sub. I know its not gonna be good, but I would like to know before I take the plunge. I own a 93 1500 now with the 5.7. It is not bad on fuel but it does not have the guts or the 4x4 and it has 267k

 

If this vehicle is running properly and you do not have a lead foot then you can expect fuel economy in the 10-12 range.
14mpg is the best that I have ever seen a 7.4L Suburban get on the highway and it was at a steady 60-65mph.

 

I can tel you what my 95 2500 4X4 7.4L gets. It runs like a champ with only 171,000 miles and has never had any major repairs I am now expieriencing limited slip chatter in the turns.
Depending on what i am pilling or pushing at the time 8-13mpg.
Jack

 

Thank you for the responce.