E85 Engine

[ntercept]

I have a 2002 Tahoe with a 5.3 L, E85 engine. My fuel economy is @14 mgp. I previously owned a 2000 Tahoe that was identical except for the engine was not the E85. The fuel economy was @ 18 mpg.

I don't run Ethanol because I can't buy it in my area. Should these two vehicles get that much of a difference in fuel economy? Can I change something on my E85 engine to make the economy similar to my 2000? Again, both vehicles were exactly the same except for the E85 engine.

Thanks for the help.

[Pro-Hawk]

This is my question also.

My current is a 04' Z71 3:73 Gear E85 motor and stock tires. Its got like 9k on it and I get 13.5-14 city / 17-18 hwy.

The last one was a 96' LT 4X4 Tahoe with a L30 motor( stock 350) / 4:10 gears. It got about 18 city almost 20 on the hwy??? stock tires also.