I have a 95 Si and it won't idle worth a crap. If it gets down past about 1500rpm it just revs it self up and then drops back down and revs up again over and over untill it finally drops really low and stalls out. It sounds like I'm sitting at stop lights reving my car like a looser. Also, when I turn my ac on it sounds like the motor starts missing on atleast one cylinder, and the hotter it is outside the worse it vibrates and looses power. Eventually if I leave it on for more than a couple minutes it starts to overheat. It is directly related to having the ac on, it runs smooth (except at idle) with it off and pushing the button to turn the ac on is like turning half the motor off... anybody got some ideas?

 

first step check your vacuum lines, that will cause the surging idle

 

I've checked the hoses, the idle control valve, and even tried another ecu, but nothing helps. I'm wondering if maybe a sensor is bad but I have no idea which one, if any, would cause that.

 

is the check engine light on? also could be possible intake manifold gasket or throttle body gasket

 

check fast idle valve and tps

 

when my h23 motor was idling funny, and turning off when it was really hot out when in neutral, i found out my head needed to be rebuilt, instead of spending all the money on rebuilding an h23 i just opted for a jdm h22a

Check everything else if all odds fail and it is the head that needs to be rebuilt just get an jdm h22a for about 1100 dollars, and use the same tranny

 

clean out or replace the idle air control valve. the same thing happen to my old car as it wouldn't idle right once you start the car then idling gets really low when you turn on the AC. Because of more load on the engine, the valve is suppose to balance it out but if it's malfunctioning in any way, get that check

 

https://honda-tech.com/zerothread/1979500

... and about 5000 other threads.

 

Any thoughts on the ac/misfiring problem?