Idle/Vacuum Surge

I have a 1987 Supra - MK3-7M-GE.
It had been setting up several years and would not start. I had to refurbish the entire fuel system including the fuel tank, fuel pump, and injectors to get it running. The engine could use a rebuild but it sounds good and does not seem to be burning any oil. Preliminary dry compression shows around 100 psi, consistent across all the cylinders.
The engine will start and runs well, but the idle surges between 1,000 to 2,000 RPMs. The vacuum surges between 200- and 300-mm Hg and the engine revs up and down. The higher the rpm, the higher the vacuum. I have isolated most of the vacuum circuits and replaced most of the hoses. Prior to replacing the hoses, the vacuum surged between 50- and 200-mm Hg (i.E, the rev cycle is higher now).
I cannot find any more leaks. I have replaced or isolated all the hoses in and. I have used starter fluid on all the vacuum points to see if I can detect any more leaks.
The surge seems to be a constant cycle. It builds and drops vacuum/rpm. A few seconds each cycle. When I try to rev the engine, it goes to about 2500 rpm and falls back to about 1,000 RPMs. The engine will idle but cycles back and forth as described. It sounds like it is loading up when I give it throttle. Each cycle lasts around 30 to 60 seconds. It almost sounds like you are revving the engine intentionally.
The engine will idle but cycles back and forth from 1,000 to 2,000 RPMs. The vacuum surges from 200 to 300 mm Hg.
Someone removed the Vacuum Canister OEM part# 25804-42010. Could this be the problem?
Replacing the Throttle Position Switch seemed to help, but I am still getting cyclic surging. Could it be the mass airflow sensor?