odd rpm gauge question

im such a noob, and ive tried searching threads but i cant find sh*te.:banghead:

hopped in my car went for a drive today...drives fine..
but when i hit 4000-4200 rpm the gauges stops...
as did the mph gauge too, at first.
Car sounds fine, its just the gauges, once i shift down or up,
the gauge drops back down quickly but normally.

a year ago i had a crankshaft crap out on me, dealer swapped in a new motor, but did say that the vtec wasnt working....could the vtec not be kicking in or something??? im slowly workin on gettin more edjumacated. but im no mechanic. thanks

It does seem to be something related to VTEC that's your problem. VTEC activates at around 4200 RPM, right where your tach stops working. But from there I don't really know, maybe check the crank sensor?

I don't think the problem is related to vtec because 1) vtec engagues around 4800-5000 and 2) while vtec depends on rpm input, it does not depend on the tachometer. So if vtec and the tachometer are both not functioning, it's the rpm signal. Check the wires from the cam position senor and crank angle sensor.