Friday night at the track in 3rd and 4th gear you could hear and feel the car back and forth dropping out of vtec and going back in. Like stuttering but steadily climbing in revs and never dropping down. What could cause that to happen?

 

check your oil level/oil pressure
check the vtec solenoid gasket for leaks
thats all i can think of.

 

Mine falls out of vtec when my lights are on, in 3rd and 4th gears. Does it only happen at night for you? Try turning your electricals off.

 

i had the same problem...oil level was a little low (right at the 1st dot), when i filled it up, then vtec was back to normal.