If you want to save gas, then you need to give your car a tune up. Nothing will help save gas more than changing your spark plugs and spark plug wires (or if you have the Ecotec, check the boots and coil on the wasted spark system). If your coils are going bad, swap them out. Clean your MAF, IAT, TPS, throttle body, and change your air filter. Changing the oil at recommended intervals helps a lot too.
Sure you'll only see 1 or 2 maybe 3 miles more per gallon, but that adds up. I was getting 20mpg with my Camaro until I changed the IAT... now I'm getting 22/23mpg. It's a big difference.
Another thing, if your air intake has silencers, take them off. The better the engine breathes the less fuel it would need to get to speed. They say the first thing you should do to a car is air intake and exhaust, and the reasoning behind that is the goal is for it to breathe better. If you can accomplish that, you're not forcing the engine as much, although in real life this is pretty much negated because people like to hear the sound of the exhaust once they get a catback or full exhaust system.
As far as intakes, there's a lot of debate about them, but I would suggest just removing the silencers. WAI/SRI systems negate themselves since they pull in hot air from the engine area.
2̶0̶0̶3̶ ̶P̶o̶n̶t̶i̶a̶c̶ ̶G̶r̶a̶n̶d̶ ̶A̶m̶
1994 Olds Cutlass Supreme
2̶0̶0̶2̶ ̶C̶h̶e̶v̶r̶o̶l̶e̶t̶ ̶C̶a̶m̶a̶r̶o̶
1996 Infiniti G20
1993 Chevrolet Lumina Z34
1989 Buick Regal Limited