i got a b18c1 with a p06 s300 v3 ecu vtec converted it breaks up between 6-7 only when in vtec it will do about 2 pulls or so in vtec without breaking up but after then it starts ive replace the dizzy plugs wires the oring under the center cam cap the vtec solenoid the vtec gaskets did a valve adjustment ghot it tuned made sure time was good still doing it anyone got any ideas

 

Coud be harness degradation. Had this issue in an em1 chassis. ECU was losing sync with distributor. If OEM harness check for wear. If aftermarket, hopefully they individually shielded the crank and cam sensor wiring.

Could also be plugs not high enough heat range. Or improper gap.

You replaced the dizzy, including the ignitor inside? If its old, do the resistance check on it to verify its not going weak.
​

 

First thing I would check is proper spark plug gap