I have a problem with P1259 code being thrown. However, the CEL goes on and off and has been doing so since last summer. It never stays on for more than a day or so and sometimes stays off for several days

Twice the VTEC limited the rpms but at other times with the light on I could exceed 4000 rpms

What process should be used? A garage started with replacing to Solenoid. My guess is the OP switch or Solenoid filter should be checked before I start replacing other parts

Help!