BTW,
1. I forgot to mention that as soon as I connect the sensor to the PCM (while scope connected), It's voltage gets cut in half or more.
2. The brake booster check valve in GM cars is different from what they call a "universal" valve in almost all store (for about $6-12), get the AC Delco bigger one ($20-35). See pics below, black is OEM while white is cheap napa universal one. The vacuum hose that comes from the manifold to the booster is about double the size on the white valve.
3. Attached are pics for the final O2 sensor simulator circuit.
