vtec controller wiring harness must be removed. map and vtec wires at the ecu must be re-connected (they get cut and run through vtec controller).

4200 is really low especially if the ecu hasn't been tuned. the tach jumping around sounds like a bad icm/dist. try changing w/ a known good dist and get it tuned.

i'm assuming you don't have any cel. if you do fix those first before doing anything else.