2007 Suburban 8 MPG HWY??!!

[FamilyGuy]

UPDATE: When I purchased the truck less than 2 months ago, owner said he had just done the oil change. I checked oil level, it was normal.
I checked oil this week, it was a quart low!
No oil leaks at all, no smoke....
Still very low MPGs and a slight miss if you watch for it.
Otherwise, like I've said before, Runs and drives perfect.

What should I check for now, compression?

 

[07Burb]

Unless tuned it is common for these to use oil like that. A lot of folks contribute the usage to the Active Fuel Management (AFM) system. My oil consumption usage went away when I tuned the AFM out of my burb.

 

[FamilyGuy]

That's a relief!
Would a tune help my MPG too?
Not looking for Prius MPG. I just want what's "average" for this Suburban.

Thanks, Burb.

 

[Dave01]

How many miles did you run in the 2 months between seeing oil level full and then a quart down?

Yes, a tune will help, but I'm still not understanding why you get 8 mpg with stock. So your shop just said add seafoam, did they do any diagnostics? Have you changed air filter, cleaned MAF and TB like Big Buttons suggested early in this thread?

 

[07Burb]

That's a relief!
Would a tune help my MPG too?
Not looking for Prius MPG. I just want what's "average" for this Suburban.

Thanks, Burb.

To answer your question yes a Blackbear Tune can give you better MPG but you should not be getting 8 MPG in stock form anyway so there is obviously something else wrong that needs to be fixed prior to getting a tune done.

 

[sixpack19]

I've gotten 10 before but it was on e85 now I get 12 on 87 gas.


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[livingez_123]

I get 11-13 around town, and 17-20 on the hwy.
never go by the trip computer, if you do, you will be sadly mistaken when you do it by hand.... the only way to get true MPG.

 

[FamilyGuy]

I do it by hand, I'm getting just over 11 MPG in the city now.
I have the 6.0, what engine do you guys have?

 

[sbubbaklein]

Have you thought about exhaust system restrictions, or clogged cat converters. Using instant MPG readout on DIC, disconnect exhaust Y pipe and let hang for test drive and compare readings.

Your Chevrolet dealer has an exhaust back pressure gauge that can be screwed into the oxygen sensor hole and the engine rpm can be increased noting if a large increase is noted.