Chevrolet Repair: 1997 malibu o2 senson, vacuum leak, horrible gas

Question
I have been getting horrible gas mileage lately.  I think my 02 sensor may be bad, how do I go about changing?

Answer
Hi Jeff,

First verify that is the problem.  You have possibly more than one O2.  Which one is bad?  You don't want to guess because of cost$$$.  It may be something else entirely.  Maybe a leaky fuel injector or vacuum leak.  Malibu is notorious for bad intake gaskets.  

You can get this car scanned for free, if you have an Autozone near you.  

If it is the O2, you need a special socket, with a slit on the side to allow for the wires.  You change it just like a spark plug.  They are anywhere in the exhaust starting from the exhaust manifold to just past the CAT.  You probably have one before the CAT and one after.  

C J S