That depends, is it carbureted or EFI?
If you have a carburetor I'd suggest the jets, float level, accelerator pump...
If it's EFI check the EGR valve, oxygen sensors, scan the computer for a fault.
Your fuel pump is most likely the cause.
12 mpg
gettin to much gas to the carb
8-16 mpg
The actual mileage that can be achieved in a Chevy depends on which Chevy you actually own. For example a well tuned Chevy 350 will do around 14 miles per gallon.
My stock 350 is 14city 19 highway.
inside the gas tank
NO, gas parts and diesel parts do not need to mix.
87 octane should run just fine.
squirt a little gas in the carb.
no... you don't want to mix diesel and gas engine parts if its not an exact match you can mess your engine up....
i would put a 700r4 that's a good one for the gas per mile and towing or 350 turbo for the other