Originally Posted by rh77
I average 80/20 highway/city and get about 27 mpg on the '98 LS Auto. There's all kinds of info out there on re-chipping for increased horsepower, but what about economy
80mpg highway?? heh are you constantly coasting down hills?
lol anyways, if you wanna run for slightly better fuel mileage, you might wanna get slightly better spark plugs/wires and distributor cap/rotor (make the spark a bit more efficient) and run some Chevron w/ Techron fuel system cleaner and/or Lucas Oil fuel system treatment/upper cylinder lubricant (only do one per fill-up, and read the directions for em...)...I did all that on my car and I'm noticing slightly better mileage after all was said and done.
if you want to go for an aftermarket exhaust so that you can help with fuel economy, make sure you keep the piping diameter not too big (like, 2.25" max) and get some quality exhaust components...you won't want an overly free-flowing exhaust that'll rob your low-end...
hope this helps some
--Brian