If they both were replaced and the code pops every 5K.... I'd say try replacing spark plugs and check the wires... It is a possibility of not burning clean BUT it would also say to me that one may be fritzin already possibly because of getting a coating for excess fuel. Also does the engine use oil at all? Check and see if you ever go low on oil that might also indicate blowby on the rings? Any other ideas here guys?

 

cayt?

 

Good point I hadn't thought about the cat bein bad... That would also make the car run rich and could cause the 1st o2 sensor to go bad due to buildup from rich running.

 

I will look into the cat when I get to my dads shop. Thanks

 

Yeah you can check your cat but there is also more to factor in too. Just because it shows up a code for the O2 sensor doesn't always mean its bad. You have to have the right ampreage and votage readings as well. I worked at a mechanics shop for a couple of years and there is no telling how manytimes people would come in saying " well auto zone told me it is the oxygen sensor" so we install it then they come back in a couple of weeks or so with the same problem and it be a a short somewhere or othere sensor acting funny. Also when you replace it don't just clear your code let it do it on it's on. After so many cycles it will clear it if it hasn't showed up. The computer don't always just pick it up right off the bat sometimes it takes a little while to turn light on. If it dont' turn it off on its on just replacing them isn't doing anything.