I have an h22a and I noticed that in 4th gear when vtec engages, it goes on and off before it stays on.

Kinda hard to explain. When I hit 5k rpm it sometimes goes on, off, on, off, then stay on. What could cause that?

I can tell this by the sound of the engine.

 

I did get a vtec error code way back when but it went away.

 

Checked oil? Maybe replace the vtec solenoid or vtec oil pressure sensor.