Idle issue


New Member
Jul 22, 2019
Civic ej9 b16a2
Hi all new to the forum need some help!

Have a b16a2 swapped ej9 and I’m having high idle issues. It’s sits about 1500 rpm and then if I turn it off and back on it can sit under 1000 rpm but it’s been getting worse. Also it has a slight misfire and pops and bangs a lot. It can run good at times only happens every so often but idle on start up is always high. Also I can be driving and then all of a sudden it will stutter and engine revs will take off and not come down unless I brake.

Sorry for the long story but can anyone help thanks! ☺


Well-Known Member
May 27, 2008
Idle control valve or a vacuum leak around the Inlet manifold area, I would use some wd40 or carb cleaner etc... to spray around IM gasket and other components in the IM and watch for bubbles when idling.

Sounds silly, but first I would check your knock sensor isn't plugged in the wrong place, is easy to mix up connector plugs around back of engine and you can do trial and error or some research on connectors/wire colours/no. of pins. My friend recently had a very issue to yours and he had his plugs mixed up. Throttle body plugs, Knock sensor and power steering level. I had the same issue with my recent B18 swap and was able to advise him lol.