after reading your last post I figured that the o2 might be cooling off with the headers, I would wrap the headers on the side that your o2. I also noted that when you pulll off the brake feed hose to the booster your o2 does odd things, your booster should be holding vac and not allowing air...
while the engine is at idle the two mose important things are the running fuel pressure and the ignition timing. the best fuel pressure is 15 psi. if it drops down below 12 psi the mixture starts struggle. The ignition should be set at 0 degs at idle with the EST connector disconnected, this is...