You might have vacuum from all the ports. However, you might be getting confused between Port Vacuum [which occurs at higher throttle opening or acceleration], used for such things as distributor advance {where applicable}, canister purge,], and Manifold Vacuum [which occurs at lower throttle opening or deceleration], used for MAP Sensor, PCV valve, Air Cleaner, Fuel Pressure Regulator {reducing fuel pressure}, Heater and A/C Systems and EGR.
I personally don't like 'T' sections, but do like using vacuum check valves. The ports at the rear of the throttle body should have the following connections:
- The highest port [with a factory bend on it] is port vacuum, and should be used for canister purge.
- Of the rest [all manifold vacuum], the largest one is the PCV Valve port.
- The one closest to the edge of the throttle body and near the large PCV port is the air cleaner port..
- The lower one [towards the centre of throttle body] on the other side of the PCV port, is your EGR port.
- The last one [high and by itself] is for your Manifold Absolute Pressure port.
Make sure all the hoses are intact [not hard or cracked], and are a very tight fit.
Good luck