question on name
 

what is the thing called next too the fuel distributor under the cold air take. it has a flapper that moves up and down... and what is its purpose.

year and model would be a big help:D

(Assuming you are talking about a 116 or 117 gas V8) It's called a 'sensor plate'. I believe it's function is to control incoming air input to the intake manifold. It is NOT a throttle plate.

the model is 1979 280E 6cyl. gas cleaning it helped but would like to know the proper name of this flapper thing. and what its pupose is in life.

It does not control the air, it measures it. "Fuel distributor" means K-jet, which means that you have a sensor plate.

As more enters the engine (throttle opening or RPM increasing), the plate forces a piston in the fuel distributor. That increases the fuel quantity delivered to the injectors. That's the very short explanation.

Cool. Thanks for the concise explanation Matt.