[johnman001]

So I took the Altitude Correction Sensor apart. Inside is a sealed expansion diaphragm, a spring loaded plunger and a snap action micro switch (Omron brand). Upon investigating it looks like the housing was slightly crushed at some point and the micro switch was being held in the closed position. I'm guessing most of the time I will be operating the car below the threshold where this sensor will be needed (1000 meters above sea level), so I will either bend the housing back so the switch isn't made or simply leave this unplugged.

This sensor had been mounted under the passenger seat (914-6 application), and it looks like the seat may have been pressing down on the can. By doing this, I probably caused my own problem over the last 30 years the engine has been in the track car.

If I do put this back in, or I find a replacement for my damaged sensor, I'll probably mount it so that nothing would potentially push down on the housing because now I know how it actually works.

Does anyone know if this Altitude Correction Box leans out the mixture 100% of the time, or only when the O2 sensor is not de-activated (when the Wide Open Throttle) contact is made?

I suppose it is quite possible that at part throttle, the O2 sensor was keeping the mixture close, but at WOT, when the O2 Sensor is taken out of the loop, the car would lean out and lose power. It makes sense if the seat pressed down on the sensor during left turns it could have pressed down hard enough to trip the limit switch.

Not sure if this is actually the root of the problem or not, but it is the only thing that I have measured that was actually out of tolerance.