4X4 Problems on a '97 Blazer

I have a '97 blazer that is getting very bad mileage. I am getting about
12-15 mpg. It did through an O2 code so I replaced both sensors and
cleared the code. That did not fix the issue. I do notice that it feels
like the front hubs are lokced up even when I put it in 2wd. When
turning, it feels like you are still in 4wd. When I switch it to 4wd Hi,
it feels like it should and also in 4wd Low. Could the hubs be locked up
in the front causing that big of a drop in mileage? If not, any other
ideas what to look for? I have recently started reading the post on this
site and I know that someone has an idea for me. Thanks for any help I
can get.

JmartinSanti wrote:

I have a '97 blazer that is getting very bad mileage. I am getting about 12-15 mpg. It did through an O2 code so I replaced both sensors and cleared the code. That did not fix the issue. I do notice that it feels like the front hubs are lokced up even when I put it in 2wd. When turning, it feels like you are still in 4wd. When I switch it to 4wd Hi, it feels like it should and also in 4wd Low. Could the hubs be locked up in the front causing that big of a drop in mileage? If not, any other ideas what to look for? I have recently started reading the post on this site and I know that someone has an idea for me. Thanks for any help I can get.

THere are no hubs to lock, jus a axle disconnect on one side of diff. If it was stuck engaged it would make maybe 1 mpg difference at most in that truck. If you have it jacked up with oversized rubber to I would say 12 to 15mpg is good as some get less. How you drive it too has some effect on MPG and in hot weather with A/C on a lot it will drop some too. ALso if it is hot and you are using 87 octane in that engine the DCM could be retarding spark a lot to control knock (you only hear it when it is so bad that ECM can no longer control it.) and this retarding can murder MPG and performace too.