If your oil level is good, take off your vtec solenoid. Make sure the shaft under the solenoid isnt sticking. The vtec solenoid is right under the fuel rail on the passenger side of the engine. It is also in front of the EGR valve system, under the valve cover breather lines that go to your intake system. Its held on by two bolts. Once you get it off, see if you can push the rod down and up. If its sticky, spray some throttle body cleaner or put a little bit of automatic tranny fluid and push the rod down and let it spring back up.
I would take a pic, but I dont have time.
GL