"rao" <rao.bayyana@gmail.com> wrote
> Also , just out
> of curiosity did you replace the part on your own. if so
> did you have
> any problems. Thanks .

Yes, I replaced it on my own on my 91 Civic. No problems.
It's a pretty easy job to do, assuming the O2 sensor is not
bound in place, and I am not the most sophisticated home
mechanic on the group either. Plenty of amateurs report here
doing it on their own.

The sensor usually is not bound. Buy a can of the
penetrating oil "PB Blaster" at Autozone, WalMart, or
similar, and soak the sensor's threads as best you can a few
hours before trying to loosen it. Have an O2 sensor wrench,
borrowed (no charge) from Autozone. Remove the exhaust
manifold heat shield and possibly a bit more interference.
Apply the wrench and see if the sensor comes free.

You might want to change the plugs, wires, rotor, and cap,
first and see if this fixes the problem. Definitely use only
OEM parts for these, too. They pay for themselves in
longevity and performance.

On the third hand, pre-emptively replacing the O2 sensor is
a good idea for a car this age.