Hello HT members I'm new and just bought a 2000 civic hb with gsr swap barred. I got a cel for a knock sensor and decided to replace it myself. I took my intake manifold off and replace my knock sensor, I made sure everything was right and plugged in after I put the manifold back on, after I was finish, I started my car and it had a high idle 2500-3k and it was like that for 2-5 mins and then it sounded like it had a misfire of some sort dropping the idle from 2500-3k to 1k-1500 fast and constantly, it sounds like the engine will die or blow up so I didn't drive it yet, any suggestions what it might be or help on this is greatly appreciated

 

IACV...make sure there is no air in the coolant first, then check your iacv. make sure its clean also.

 

1.throttle cable tension
2.vacuum leaks (did you replace the IM gasket?)
3.bleed coolant

 

Update

Turns out my gasket for the manifold and the engine was ripped when I put the manifold back on, I bought a new one today with some sealer, installed it now its better thanks

 

Just a note in the future no sealant is needed only the gasket but good to see that was the only issue.