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Ok so I dont use forums all that much so if i missed the topic on this i apologize.
So heres the problem, I swapped a blown engine out of my 1998 Civic DX (coup) and had to use a 97 wire harness. It started up all fine but after about 3 minutes of running it bogs out while idling. I havent put it on the road yet so I couldnt tell you if it bogs while driving. If you can imagine it sounds like .... " vroooooooooooom blaahh vrooooooooooooooooom blahh " over and over, . I havent done timing on it even though I did have to change distributors but i assumed timing wouldnt make it bog like that. Someone mentioned an airlock in my cooling system but i tinkered with that and didnt seem to help. Does anyone have suggestions as to where I should go with this?
Also it does idle a little high to the point where no gas pedal is needed to take off (Manual).
Im not sure what else can cause this besides a sensor of sorts so ill mention a few things:
Has catback exhaust
Cold-air intake
swapped engine has only 127,000km

I would appreciate any help.

 
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After the engine is warm, it idles up to about 2000 RPM, then drops to 1200, then repeats that cycle almost endlessly?

Check for vacuum leaks, IAC stuck open, low coolant level.

 
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Thats pretty much it. Thanks, Ill give that a shot, might not be for a few days though.