Hello. I have run across the same problem before, one time it was a bad ground on the valve cover and engine block, the other time it was the cam sensor. My best guess is to check the large multi ground conn. by the rear knock sensor and just below. Take it off and insert a star lock washer under the conn. and tighten bolt. Take the ground off the left side of the valve cover near the oil fill and do the same. Report back. I may have other ideas. Pauli