Hey guys, this is my first time posting here. I have a 2000 Honda Civic si. Not to long ago I changed my stock intake manifold to skunk2 manifold, after changing it the car has been having idling issues. When turned on cold start it idle at around 2k and you can hear a really lound hissing noise coming from the throttle body area, the Rpms take a long time start dropping but when driving the rpms keeping dropping to the point the car just start to want to turn off.. I tried checking where exactly the hissing now was coming from so I took off my air intake and seen theirs 2 holes in the tb and put my finger on the bottom hole and the idling calms down. I just want to be 100% sure it's the iac valve that's giving me idle problems before buying one. Is there anything else that could be causing bad idle to where the car wants to turn off?

 

what is your base idle set at? did you even reset it after the manifold install?

 

The tps sensor? If so, then yes I tried my best to adjust it.

 

You don't just adjust a tps sensor, you need to calibrate it but that has nothing to do with your base idle.

With regards to base idle, you need to adjust the base idle to whatever the spec is for your car. Do some searches for how to set it and also find your spec. There should be an idle adjust screw on the throttle body. Make sure you do it the correct way.

 

If you think it's the idle air control then take it off and clean it. Google "idle air control Honda tech" it will show you a step by step. I just did it and my idle is almost perfect now. Might fix your problem. And definitely Calibrate you tps after installing a new TB