Theres probaly many of these ask, but i'm in a hurry rite now, though i throw this up for an answer. Anyway my CEL comes on at above 5k rpm, i'm gettin no VTEC, so i check the code but not sure if i'm seein a code 21 or 22. but if I leave the car for a lil bit the CEL is gone. I'm not sure if its a the VTEC oil sensor or the VTEC solennoid

 

21 = spool valve
22 = presure s/w

Low oil pressure was my cause, make sure you have no dents in your oil pan, i had a dent and the pickup was mushed against the bottom restricting flow at high rpm's

-Eric