I checked the wiring seemed fine.... looked over my grounds... What could be causing a code 21? It is only after a little while of driving, after the car is warmed up. If i let it cool down (overnight), the next morning it is fine again for a while, then the check engine will come on spuratically. However, it doesnt always happen, i went a couple of days without it.

Any help?

 

If the wiring is good, the connection at the ECU is 100%, then your problem is the VTEC soleniod itself. They do go bad, so that is a posibility.