1997 civic ex idle problems with a/c on

you can get harsh, jittery idle if the timing belt is loose because it
causes the timing sensors to lash. check the ignition timing. with the
service connector in place, if you see the timing marks jumping about,
the belt probably needs tightening.

other than that, make sure all the ignition gear is in good running
order - replacement with oem cap and rotor is a good idea, along with
new leads and plugs. [some high end plug leads, the spiral wound
variety, can be better than oem, but be prepared to pay about double.]

if and only if you've looked into all the above, and it's not fixed the
problem, and you've cleaned the throttle body, run injector cleaner
through it, etc, /then/ you can adjust the throttle body idle position.
but normally, you don't need to because normal idle behavior is
computer controlled via the e.a.c.v.

 

Ok, i just bought a 1997 civic ex with an automatic transmission. It
runs great, but i am noticing a harsh idle when i come to a stop and
the air conditioning is on. If i am at the stop and i dont like the
way the car idles, i just turn off the ac and the car will idle at
around 1000. Problem is if the a/c is on then it will idle around 500
and give me an annoying shake. I am no car expert but my dad thinks
that i should replace the spark plugs and wires and adjust the idle
higher. Now if i do this won't i burn excessive gas.... the draw to
this car was the price and gas mileage! So what should i start
checking first with this problem?

 

Other than what jim beam has said, check your Electrical Load Detector, and
the A/C idle-up.