Hello all,

My wifes C70 ( Iknow this is the S70 board but it seems that no ever looks at the C70 board) has been having rough idle and low gas milage issues.
I read the codes and got P0172 system too rich, P1171 Manf control fuel air metering and P1133 Manf control fuel air metering. I could clear the codes and it would run better for awhile but would go back to running bad.
Upon investigating I heard a momentary vibrating/humming noise from a part that has 3 vacuum hoses going to it and a 2 wire cable attached to it. The part is located next to the MAF sensor on the air cleaner to turbo vent pipe. The 3 vacuum lines all go back to around the turbo area.
I disconnected the wire cable from this sensor and the car will have a rough idle upon starting but will drive and idle in gear alright. When I reconnect the wire, it goes back to running rough. I took the part out and tryed to clean it out with some brake part cleaner but it did not help any.
I reread the codes and do not have any of the previous codes but have a P0243 turbo/sup wastegate soliniod A malfunction.
Any one have the answer to what this part is called and why the car drives better once you get it going with it being disconnected?

Steve d. '94 854 120k, '95 855t 148k, '00 C70lt 81k.