my cruise control seems to be slow to engage. it appears to be on when selected but weak and will slowly build to engage at the selected speed. any ideas about what the problem may be. there doesn't appear to be any detectable vacuum leaks in the hoses or connections.

Any suggestions on how I can get at the t-fitting without taking the booster off?

It's a flimsy plastic T-fitting that can easily crack... if you pull slighlty on the vac lines that go behind the booster (leading to the foot peddel plunger) you'll see it.

the T-fitting appears intact, no cracks. is there a way to measure the force of vacuum from the vacuum pump? could this be the problem?

It's adjustable so you need to make sure it's aligned correctly (opening/closing fully)... it's pretty simple... if you look at it you'll see how it should work.