I just went to get my crx smogged with stock D16 engine and it didnt pass. The guy told me that HCM is high because due to bent valve and that it is misfiring in some rpm. The guy told me that it could have been a bent valve, etc. Then it dawn on me. I overheated my engine a while back and i changed the headgasket and i only got the head resurface but i didnt get a valve job. Oh Btw, engine would often stutters when im driving it down the freeway or road. Could this be a bent valve?