I have a 4 cylinder v-tech honda accord, approximately 2 weeks ago I put on a Cold air intake and new spark plugs. When I started the car today the idle fluctuates from 1,000 to 2,500 rpm's (in park and neutral). So after driving approximately 4 miles I poped the hood and noticed that the CAI came off the engine so I put it back on and made sure the clamp was gorilla tight. After that the check engine light came on and the engine idle continued to fluctuate. Any help is much appreciated. Thank you very much

 

Something you did is loose. It shouldn't pop a CEL. I'd recheck all the sensors that is related to what you disconnect.

 

check the CEL

 

This is the first thing you should always do. It comes on for a reason...