I replaced the intake manifold gaskets and have been fighting a 171/174 lean codes since then. I've check everything I could..spark, fuel pressure, etc... and I just noticed something. There is a black plastic fitting on the top of the intake manifold that the hose from the brake booster connects to. We broke one of the ears that holds this fitting in place and I'm wondering if that's my problem. I've called around and no one knows the name of this fitting. Anyone know? I've searched intake manifold vacuum fitting, manifold check valve, and anything else I could think of and no luck. Thank you.

 

do you have a picture of where it connects or what the part looks like, would be a better way to go.

 

Probably Booster Check Valve issue.