okay...i just got done putting in my b18c1 and now a problem...the problem is with the rpm going up and down when your about in the 1500 to 2500 ....to me i think it might just be one of my sensors from the throttle body or intake manifold but not sure which one....the idle is fine at 1000 rpm but when u push alittle gas to make the rpm stay at 1500, the rpm would go up and down....

 

Take off your idle air control valve and clean it with throttle body/air intake cleaner.

I dont exactly know where its at on your motor, but im guessing back of the intake manifold? should be 2 10mm bolts holding it on, its a cylinder looking thing next to the throttle body.

 

what year engine? what year car? whats done to it? it might not be your iacv , it could be evap purge solenoid. tell me whats done and what year car and engine is?

 

oh man, the iacv can be an issue, but it doesnt go bad, Hondas in general always have that annoying bouncing idle. most of the problems of the boucing idle can be related to air leaking anywhere from the intake manifold, brake booster, just check it out.

I had a bouncing idle problem that was going on for close to 2 months in my r, didnt know what i had everyone look at it, tech's everyone i knew, just one day out of luck after changing oil, and fillin up fresh gas, hit vtec then fix it?, but i cant see how oil and fuel could have fix the problem, after talkin to a few people They say It could have been air in the coolant. CHeck coolant, after driving or what not, see if the coolant is still in there.

Goodluck