Hi everyone, I have a 2001 Bonneville SSEI and the boost needle stays at -1 and doesnt move at all except when I start the car and it jumps up and down like all the rest of the needles. I just bought this car a couple months ago and it has lil over 90,000 miles on it. It runs great until I get on the highway and cruise for a while, then when I go to slow down the car acts really crazy on me and hesitates when I go to take off again and I am not sure if it has something to do with this or not.

Check the vacuum T fitting under the nose of the supercharger coming out of the end of the lower intake manifold (passenger side).

I have checked it and followed all other lines but cant find a leak or loose hoses.

Would the BCS cause this problem?

It could. Have you scanned the car for any codes, especially if you are having hesitation problems.