Since I am new to this forum, I'd like some help on this subjuct. I recently purchased a 99 Civic and has around 230,000kms on the clock. Just two days ago the engine light came on. I don't have a scan tool, so I'm trying to find out what problem is first hand.

Today I changed the distributor cap & rotor, plugs (NGK) and wires. BTW, it was in need of replacing. The notice the car is "sluggish" & "missing" during accelerating. At some RPM, the vehicle "jerks". From my experiance, many owners told me that when they had higher milage honda's, at some point the oxygen sensor will need replacement. What I want to know is if this is the case since there is 2 oxygen sensors, which one is the most common to replace?? And which one is the most important?? The oxygen sensor on the
manifold or down after the catalytic converter??

BTW, this all started because the cool nights here in Canada due to frost.

Thanks for any input !!

Civic28

 

front one on mani is most important to replace.. also most auto stores will scan your car free and tell u what the check engine code is.