My 2003 Accord run very rough and bucks at about 2300rpm. Check engine light is on. I’m getting the P2646 code.

I read on this forum that P2646 code indicates to replace the Rocker Arm Oil Pressure Switch (VTEC Oil Pressure Switch).

I did this and still no change in performance. My oil was changed and currently has about 1800 miles on the new oil.

Someone suggested to change the oil again and add 2 ounces of Marvel Mystery Oil to the oil.

My ABS light is also on.

Can someone please provide an option and suggestion of what to do?

Thanks.