There are three MAP sensors right next to the intake manifold/supercharger on the right side of the engine. My question is are all three supposed to have a vacuum line connected to them, On my XLR V the first and third one have vacuum lines but the middle one does not. This doesn't make sense to me but what do I know. I could not find a hose that might have slipped off so either the previous owner removed it or there never was one. Any help?