What causes a 2000 honda accord 4cylinder vtec 2. 3 engine not to rev over 4000 rpm?

What causes a 2000 honda accord 4cylinder vtec 2. 3 engine not to rev over 4000 rpm? - 1

Smashing it to bits at 3999rpm would be one way of not causing it to rev over 4000rpm.
Not exactly helpful, but it answers the question and is correct.

How hard are you revving it? If you have an automatic transmission that may be why.