Hey Jim...
I have been where you are! I would take a very, very close look at the wires into the coil pack and coming out of the Cam/vrank angle sensor. On your 1.8 it is at the back of the head on the driver side. What happened with a friend last year is that the wires frayed a bit and sometimes there would be enough connection and sometimes not. At an initial look... they seemed fine.

The wires can take a pretty sharp turn there and on mine the plastic aroudn the wires was fraying. I made sure the connections were good on mine and "painted" the wires with some "liquid tape" to seal and reinforce the wires and connections.

This is a pretty good bet, but please let me know what you find!
Brad