blacksiVTEC

I'm only the seconded owner of this 00 si I bought it with 71000 on it now its has 185000 so about 6 months ago I'm going down the highway and i felt something give loose it felt like in the peddle like a lose of power and when i came to the first light it started this rough idle ****. So I've replaced everything from the plugs back and still the same thing. So I'm thinking its burnt valves because of the misfires on 2 and 3. I really just need to know if its a sensor or am I gonna have to break the head down and rebuild it up. HELP PLEASE THANKS