i think i've seen a similar problem posted on here before but i couldnt find it.

my basic setup: ls/vtec with PR3 ECU, stock 1st gen B16 intake mani except for the injectors and B&M FPR, GSR header, and VAFC.

what happens is if i'm at a stop and rev my engine past 2k rpm the revs will bounce up and down about 500. so say i rev to 2500rpm, my engine will bounce from 2000 to 2500 over and over again. all i know is its not my EACV. i was thinking that maybe i switched the placements of my o2 sensors when i changed my header but i havent been able to try switching them yet.

anyone know what my problem is and how to fix it?

thanks

 

Is it just the tach that is bouncing? If so, check the wires.

But my friend's ls/vtec reved up and down when we unplugged a vacuum hose on the manifold. I'd double check the vacuum hoses. Good luck.

 

yeah its definitely not just the tach. i'll check the vac hoses again.