Still bad gas mileage about 25

I installed a new o2 sensor, and we thought for a short period of time that my computer system was messed up, bu, we tested it and everything is ok, so no i do not know what to do getting 25 mpg gallon is not very good so what else can i do SOME ONE PLEASE HELp me

HELP ME SOMEONE i can not figure out why my car is getting chitty mileage, SOME ONE PLEASE REPLY!

thank you

Might check to see if your tailpipe has black residue, might be related to your fuel injectors. Might try a really good fuel injector cleaner that you add to the gasoline tank, see if helps, if an injector is bad, probably won't help, but it might free up a stuck fuel injector, etc...

I understand your dillemma. My 95 Aspire has the same problem, and through some fidgeting, I believe I might have figured out the answer, though I have not time tested the solution yet. Needless to say, my Aspire was getting bad gas mileage, and among the things I noticed was carbon-smelling exhaust, overcooling, and eventually random cylinder misfire. The spark plugs were carbonated along with the exhaust, which is indicative of a rich fuel mixture. Like you said, most likely explaination is O2 sensor. However, the voltage readings checked out in accordance to Ford specs. Also the ECM checked out, and the fuel injectors appeared to be operating correctly (stethoscope method). I found out that the Aspire tends to operate in closed loop mode when the engine is not up to normal operating temperature or doesn't stay there for over two minutes. So I began to diagnose and fix the overcooling problem which ended up being a stuck thermostat. My Aspire is already running tremendously better, the carbon smell is gone, and it appears the gas mileage has gone up- though I haven't given it a long term test to make sure, but it looks positive. Hope this helps.

I have a 97 Aspire. It has never gotten good mileage although it looks as though it should. No power steering. Drives like a tank! For the past few months I've had a transmission fluid leak. Can't be easily repaired but as long as I park on the street, I just monitor it and add fluid when needed. It only has 68,000 miles on it and I'm going to drive it until it literally falls apart. For the kind of car it is, it has fantastic pickup and I can always find a parking space. My friends think I'm nuts to favor this car over my other.....a 2005 BMW 525i......Oh, well!

I have now had the opportunity to drive my Aspire for a while after the thermostat I replaced. The gas mileage has improved slightly since the car is now running at normal temperature, but it is still lower than normal. I am now looking back into the computer, fuel injectors, and fuel regulator.

Have you had a smog check? :uhoh: I bet the answer lies in the results of the test and the smog tech will be able to pin point your problem with testing your exhaust gasses.
One other thing you might want to check (I've only seen this once) are the brakes. Make sure you don't have a caliper not dragging or a shoe not properly adjusted right.