What does this do, and can I cap them off at the TBI and the valve cover? Also, what is the line going into the rear of the TBi for? And the front one? The small ones. Thanks!

 

You don't want to mess with those. If you take the PCV out and don't put some kind of breather in, you'll have lots of crankcase pressure and oil that turns to tar in a week.

The ports on the front, at least on mine are (left to right): EGR solenoid, PCV, evap canister.

The rear port is your MAP sensor hookup.

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'92 Astro, GM crate 350, Holley Pro-Jection Intake, MSD 6AL, 3.42's, 2.5" exhaust, Flowmaster 40 2 chamber, B&M 2nd stage shift kit, 255 60 R15 tires on AR-727's, Polished & Bored TBI, Custom EPROM in progress

 

Chad,
you can cap the hose for the PCV and for the air cleaner,but thats if your going open element air cleaner, "Dont Mess with the one in the back of the throttle body, that is for your MAP sensor, thats where your Sensor gets its main vaccum from you pull that and you will not like the results, and you ECM wil not like it either

mike

 

I am still debating whether or not it is worth in it to have the evaporator canister. What does it do? and will it hurt anything if it is removed?