I just found this board so please forgive the probable duplicate question asked elsewhere, but I have a 1994 G20 A/T.. Never get more than 26 hiway @65-70mph and around town avgs somewhere between 17-19. To me this isn't up to snuff. I've been told that replacing O2 sensor will alleviate problem (i.e. better mileage by as much as 3-4 mpg). Is this expensive part? Can I do it myself (I'm fairly mech. inclined). Any info is appreciated.
Thanks,
metmdx
