For the mileage to differ so much, something must be terribly wrong.
Were the sparks plugs sooty?
Automatic or manual transmission?
Any difference in performance?

Answered by KHLow2008 (expert)
39,832 answers provided

It is an Automatic. Their isn't a Difference on how it drives. I changed the gas cap too. It still runs the same from when I got it but I drove it from Texas to Philadelphia and now it's eating too much gas and I couldn't figure out why. And once the car has been left on. The car smells like eggs. It's coming from the muffler. So I think it meant be the o2 sensor.
The spark plugs were just black when I replaced them.

Response from Captainwinkie
2 questions asked

No, not the O2 sensor but rathr the catalytic converter that causes the rotten egg smell. The engine seems to be running rich to cause that. The best way to go about is to lug in a scan tool to perform a diagnostics on the various sensor operations.

Answered by KHLow2008 (expert)
39,832 answers provided

So what do Suggest I do about the gas problem that I'm having?

Response from Captainwinkie
2 questions asked

Since you have problems, you need to be checking out what is causing it. The catalytic converter could be bad. Engine could be running too rich and for these a scan tool would help tomonitor the various components to find if any sensor is working out of range.

Answered by KHLow2008 (expert)
39,832 answers provided