The rubber nipples I used to cap all the factory vacuum ports are cracking like hell after just two months of use (less than 200 miles!). Removing every port and sensor from the intake manifold seems like a safer bet than relying on these tiny, disintegrating POS.

Does anyone have a complete list of sizes and styles of plugs for a factory Toyota intake manifold (1989 RWD)?

 

LCE sells a complete set for a decent price. You could buy them individually at a hardware store but there is one plug that needs a shouldered edge to seal correctly, this one may be hard to find. Just go with LCE and call it good. It comes with all the plugs you need even if you have an offenhouser intake. With a stock intake you will have a few extra plugs left over.