egale mark, have you tried a 16144288 ecm in your suburbun? i have been tunning a747 on my 6cylender and after tooning it 1 mpg more than the 288 that has a stock chip. there is not as much stuff that you can change but some one that noos more than me may get a lot of mpgs out of this { rage doll ecm } mine is a 6 an 8 is easyer to get what you need.