Hello ...when did your vtec kick in? Sounds like possible limp mode, dunno for sure. If you have low oil pressure as stated before, that could cause no or late vtec engagement and possible limp mode. Hope you can check your oil pressure with a guage to find out for sure that its not too low. If you jacked up your engine lately with a floor jack and dented your oil pan up, that also could cause low oil pressure by obstructing the oil pick up. Hope this helps, if not , disregard everything after Hello.