My 1990 9000 carlsson engine(2litre) has a part I cannot identify. It is a small plastic block with two vaccuum lines screwed into intake manifold between #2and#3 cylinder. One of the lines has a short pipe and then is blanked off. The other goes to the inlet at throttle plate area. I could not understand this as surely these two areas experience same pressure? My friends non turbo 9000 2.3 has different setup, his has the coolant temp sensor roughly where my mystery part is,whereas my CTS is between #1and#2! Any ideas?!