1st what is the vac thingy on top and what does it do
2nd will a 4gen tps work on this tb

 

That's the "throttle opener" which is a vacuum actuator. When the engine is not running (no vacuum) the end of the spring loaded actuator rod is used as the throttle stop whereby the throttle is "cracked" open to assist in engine starting. As soon as the engine starts and develops vacuum the throttle opener pulls the rod back and the throttle will close until it contacts the fixed stop on the TB housing. It appears to be used only on certain 2000 cars, I believe.

 

^thanks^

 

Yes, I'm currently using a dek tb with a 4th gen tps on my 4th gen.

 

Could I use that vacuum port for feeding seafoam? I see few advantages over brake booster or PCV method:

1) Small diameter hose so that rate of injection can be better controlled
2) even delivery of seafoam to all the cylinders
3) possibly cleaning of the throttle body without taking apart anything.

Disadvantage:-
what if there is something under that vacuum hose (throttle body end) which might get douched in seafoam resulting in $$$$ damage? :-(

Does somebody have a spare throttle body to see if that port can be used in this fashion?

Thanks,
- Vikas