2000 Ford Escort fuel economy problem
 

I originally posted this in the Ford Escort forum, but it doesn't appear there are many people who view that forum, so I decided to try here.

I recently became the proud owner of a 2000 Ford Escort. The engine and automatic transmission are in excellent condition. There are some minor problems, but these are being fixed.

The problem is the fuel economy. I've been keeping track and I'm getting less than 20 miles per gallon. According to the government rating, I should be getting 22 mpg in stop and go traffic and approximately a combined 26 mpg. User experiences on other sites indicate that this estimate is correct or even underestimated. I am an experienced driver who is easy on the acceleration and speed. This is Houston, so sometimes using the AC can't be avoided, but I usually just roll down the windows to save on gas. The tires are new and properly inflated.

The only thing I can think of that might be affecting this is the fact that when you put it in drive, it will accelerate to 30 mph on its own without pressing the gas pedal. Higher speeds seem normal, however. Idling seems fine. When the car is started, it idles high at first (2000 rpm), but immediately eases down to a bit below 1000 rpm. I also suspect a belt might need to be replaced, as sometimes turning on the AC will shake the car a bit until it's accelerated a little.

What can I do to increase the fuel economy to a more typical experience? Is there anything I should look at other than what I've already described?

Also, I've seen a product in the auto parts store that is supposed to be added to the freon and claims to make the AC run better and save gas. Does anyone know about this? Does it work as advertised?

Thanks in advance.