Looking for the 3 way rubber grommet replacement.
The piece that connects the vacuum hoses to the top of the throttle body.
Anyone one knows of an after market piece. Mine is cracked and leaking and brittle.
I checked with my local GM dealer. The part you are looking for comes in a kit with tubes, a regulator and solenoid. It is GM Part # 03539219, HARNESS, EVAP EMIS CNSTR PURGE (INCLS 2-6). My discount price was $125, wholesale about $145. They don't just sell the vacuum port connection. I suggest your local salvage yard. Also check the other rubber connection at the solenoid.
I don't know how much a leak here would affect performance since it is tied into the evaporator purge system. Probably not much, if at all, except for a burp at startup. Hopefully others can comment. Ranger, you out there?
The problem with a leak in the EVAP system is that it sets the "Check gas cap" message and then eventually sets EVAP codes which will fail emissions testing. EVAP only purges the fuel vapor overflow canister under specific cruise conditions when a small amount of extra "air leak" will not upset fuel mixture calculations, so a full-time vacuum leak is not good.