homeskillet305;1370395 said:your missing the little air filter for the vacuum line that goes to the map sensor
pbasil1;1371787 said:Its a check valve that went to my stock boost sensor on my car. Not sure if thats what really is supposed to go there, but thats what was on mine.
If nothing else you can plug it or add a vac line nipple. IIRC its a 3/8" NPT fitting.