2001 Chevy Tahoe Increase gas mileage

What is your mileage now?

I will be honest -- It will cost you about $5000.00 to put a better fuel injection system on the motor and about another $500.00 or so to upgrade the computer to work with the injection upgrade. Even with this -- you will only get 2 or 3 more MPH. Your current mileage is great for a V8. With 100000 miles on the engine, you should do a 100000 tune up. You should change the spark plugs and fuel filter- test the plug wires and coil packs. Check or replace the air filter. Changing oil sometimes makes a difference -- I found that Castrol 10-30 fully synthetic oil actually increases fuel mileage slightly. It is probably time to change the transmission fluid and filter also. If you change any ignition part (spark plugs/wires ETC.) Make sure you use A/C Delco parts ONLY! If you don't you will find that anyother ignition system part will cause problems 'down the road'.