[urq] stumbling under boost

[Gary Brown]

Hey guys-

 Having an issue...

My 85 urq runs great, except it has developed a nasty
stumble at full throttle and full boost.

Can't find a vacuum leak and duty cycle readings seem
to be correct.

While crusing at 4k RPM, part throttle, I see around 
66%. Full throttle is 77-79%.

Rotor was a little crisp, but I sanded it back to its
shiny self.

No difference.

Thoughts?

Gary