What sensor controls the boost gauge on the 00 Bonnie? Mine has apparently gone out because my gauge just sets just below 0 regardless of throttle position. I have checked the vacuum lines & haven't found anything so I'm assuming it'* the sensor.

Do a simple test. Pull the vacuum hose/elbow off the bottom of the BCA (round black cylinder). If your boost doesn't return like it should, I wouls strongly suspect the BCA if you really don't have any vacuum leaks

there is a MAP Sensor right behind the SC on the rear of the engine

that gives the imputs to the Gauge and the PCM

Yup....the MAP sensor is the only one that sends a signal to the gauge in reference to actual pressure inside the Intake Manifold.

Cool thanks guys I'll check it out.

BTW, I do still have Boost just no gauge reading. I think the first person mis understood my question.

Well after another look I found the culprit. It was the T fitting under the SC snout. It was cracked apart at every end & pretty much fell apart when I touched it. I didn't catch it before because I didn't feel around on it just glanced over everything & it looked ok for what I could see. Anyway I replaced it & problem solved...