How long since the 60K?
Mine did this until recently. I've done two things in the last couple weeks, one of which fixed the problem...
I pulled & cleaned the intake manifold, so while I was at it I retensioned the timing belt. Just loosen the tensioner hold-down bolt, allowing the tensioner spring to take up any slack in the belt, then retighten. Mark Nunnaly's 60k video mentions this. I've almost got all the stuff to do my 60K, so this was just stopgap stuff.
I also dropped in a K&N filter element. Personally, I think this is what solved the PT ping - better volumetric efficiency when only the primaries are open.
FWIW...
