it doesnt seem to do it all the time now that i have bled the coolant system. i did however get an iacv code once about 2 weeks ago, but nothing since so i never thought to replace it. as soon as it starts to surge ill turn off my car. ill start it right up again right away and the problem is gone. it idles nice and smooth at 750 rpm. any ideas why this is happening?

 

that happened to me, for me it was either a vacuum leak, but also clean your iacv... two birds with one stone

 

Id advise to do one at a time. If u do both u dont know which one fixed the problem. Thats what the whole purpose is for to find the problem. Idle-- small vac leak possible. the IACV might be going out. when the cel light came on it came on for a reason. take it off check it out. check the sensor with a ohm meter. Clean it up good. What year is ur motor? Some HONDA's have a high idle valve, and if that starts to go out then it can cause idle issues. also when u bled ur system did u jack the front of ur car up a couple inchs that way the air will travel twards up and out the radiator. If u suspect a Vac leak take a small torch bottle open it up so the propane comes out and go around the gaskets and intake (TORCH NOT LIT!). Do it when the idle happens. If u go around with the propane and the idle stops u have found a vac leak. I had the same problem. first it was the High idle valve, then intake mani gasket then the iacv went poop. I hope this might help u some if not let me know how it went. Give me some more details!!! good luck!

 

i tried an old iacv sitting in the basement that i know works. i really dont think its a vacuum leak. i drove around all day with my iacv unplugged and set idle to 750 and it ran great. if it were a vacuum leak, the idle surge would still exist. but, i cannot think of anything else now. ill play around with my timing tommorow

 

i now know that its got to be something to do with the iacv. its not timing or a bad map or vacuum leak etc. im thinking it has something to do with the electrical.

i need to know how the iacv works exactly because im thinking its my battery, alternator or a combination of the two since i am using a ctr n1 crank pulley. this pully was designed to decrease the drag of the engine by decreasing the amount pf times the pully spin over. so when im on the highway i dont think my car is charging well enough or something. maybe my iacv is getting the wrong voltage