Just as the title states. I have a really high idle, so I need to know how to adjust the bottom throttle plate. I put a flash light to it and I can see light from the other side.

 

I don't believe it is adjustable. The air adjustment screw under the right side of the TB should be used for minor adjustment. For big adjustment, unlock the lock nut on the front of the TB, and change the screw height.

 

Then, wat's the solution. I guess it's time for a new TB huh?

 

Doubtful. Throttle bodies are simple mechanical pieces. Read the FSM about how to adjust idle. Also check for vac leaks.

Plenty of threads on how to do both if you search for them.