did u check ur engine oil level...
sometimes this could happen ...
o2 sensor very rare... since just bought..
my b18c until now runs no prob at all...... cheers
if as you says CEL still there and vtec open as normal most of the time was your O2 sensor
and you having sometime got power sometime not
you could check like this turn on your key CEL will off after 2-3 min the CEL come back again its will normally O2 sensor spoil
to confirm just plug in diagnostic machine/ hondata k-pro its could tell you everythings