Originally Posted by shangyer
No, it is not broken. These days I found the mpg of my car almost below 20 (city drive) and I wanna tune it up somehow. I havn't replace the O2 sensor and wires set for almost 7 years! I think it is time to do some work 'cause I wanna keep this 93 teg for a while!
If it's been 7 years, you're due for a new O2 sensor. They do degrade over time.