My old Neon's been dropping it's gas mileage (slipping down to about 27mpg) and pick up. It has about 147,000 miles. Everything is computerized, so what could be done to fix it? I thought for months and then it hit me. THE SPARK PLUGS!! The engine has no points or distributor, but it still has good old fashioned spark plugs that I could replace myself.
So, I did. And WOW the performance is way up now! Back were it was when I bought the car. The traffic light goes green and I mash the accelerator and off we go. Man this little ol' Plymouth is fun again.
The down side is the gas mileage still hasn't improved much. I guess if I could get my foot out of the throttle it might help! :)