ZUK - It definitely seems as if the timing is retarded under load. It did ping before the tuneup. I'll unplug the KS and see if it pings.

DRT - How can I test the EGR?

MN- Problem began shortly after tuneup with wires and plugs...no cap/rotor. I'll check about shorting the diag plug for the timing.

All of these suggestions seems to be leading to the same effect that I'm experiencing so I'll try one at a time and see what happens.

Thanks.