I have a 98 SVT. I drive 50 miles round trip a day. 48 of the 50 are interstate. 79k on the car and I was getting 21.5 mpg w/ the original plugs, wires, fuel filter and the CEL on for a bad O2. Changed all of that and added a K&N to the factory box and now I am getting 21.2 mpg. I thought I would get a little better. And this w/ the A/C on or off.
