Engine skipping
 

Starting several months ago, I noticed an occasional skip/misfire when cold. The problem severely worsened this past weekend when normal operating temperature, check engine light came on, went into limp mode and registered a P06060 code. I've been running an Edge Evolution set on "economy" tune. When I set the Edge back to stock, the check engine light went out and the truck returned to normal.
Today however, I felt a slight skip when the engine was cold but it cleared up quickly and ran normal.
Coincidentally, the occasional skipping began when I purchased fuel at an out of town independent station. I've changed fuel filters. But it was only a few weeks earlier I installed the Edge Evolution.
Any ideas would be appreciated. Could it be the injector wiring harness?