Check Engine light came on intermitantly around a month ago and 2 weeks ago started to kick out at 3800 rpm and kick in at 3400 rpm. The codes came up as.
- P2646 Rocker arm actuator system or stuck off.
B1 Variable valve train, electronic control with single oil pressure circuit.
- P0134, B151 Oxygen sensor circuit no activity detected
- P0661 Intake manifold tuning valve control circuit low.

I checked with friends and various internet sites and most information points to Vtech solenoid and oil pressure switch as the problem.

Any advice on what the problem could be and recommended fix would certainly be appreciated.