UrQ low boost problems

[Andrew Finney <afinney@tamsconsultants.com>]

I thought this problem was related to the summer's warmer
weather, but I've given up hope as the temps slowly drop as fall
approaches. I used to get 13psi boost in the dead of winter
from my TAP'd 1983 UrQ, now all I can get in 4th and 5th gear
full throttle is 8psi. Where'd the boost go? I have a VDO 0-30
psi gauge that was originally tee-d into the FTCU line, but
recently moved to the original boost gauge pressure line for
dash mounting purposes. Both locations read about 8psi. I've
replaced just about every vacuum line in the engine
compartment, new o-ring on the intake plenum, new fuel
injectors w/ inserts (possibly w/ no insert seals), new viton
sealing rings, new accordian hose, new fuel pressure regulator.
And while we're on the subject I'm only getting 22 mpg on the
highway. Is that reasonable for an UrQ. I do realize that
positive manifold pressure is inversely related to fuel mileage.
Any thoughts? Any things I should check? How do I check the
wastegate, other than the 4th or 5th gear, feather the brake
method? Thanks.

Andrew Finney
1983 UrQ.