lag before vtec, i need help

i have a GSR and ive been having some problems with my car lately. Around 4k or so my car hesitates and feels like there is something holding it back until i hit vtec, once i hit vtec it pulls hard. Heres the tricky part, when my car is cool, like within the first few minutes of driving before the oil heats up… the car feels real good, no lagging at all but i dont have vtec. it passes 5800 without changing over and the rev limiter kicks in around 7400. I beleive this is due to the temperature of the oil becuase i know it has to be a certain temp for vtec to kick in. My question is what might be wrong that would cause the car to lag when vtec is working and be fine when vtec is not working?
if this makes any sense, any help will be greatly appreciated

here take a look at one of my post. Help car struggles through 4000rpm

for a while it went away after i rewire the lights on my car (cause the guy before did a bad job on it). now its back. i just noticed it these 2 days. now i’m thinking the clutch or the ecu. going to change the clutch when i got the money. but i’m still clueless to what causes it.

actually it takes a certain oil pressure for vtec to activate,… maybe your oil is low.

mine does this too i dont understand im gonna change the oil and get new ngk plugs!!

what kinda oil and what weight is recommended i used 5w30 in my old car what in the gsr do we use?

i use 10w30. its recommeded for yr round, except for colder climates 0 - -30 (neg 30). says in the manual.