[twobjshelbys]

At low RPMs there is enough air that gets back into the pipe to confuse the controller at idle. I ended up moving mine to one of the header lines (yes, just one cylinder where a bung had previously been installed) and it runs much better at lower RPMs. Also, in the collector or side pipe the angle of the sensor is such that it can foul and get moisture built up and I ended up having to replace it. The ideal position for the sensor is straight down. In the Cobra there is no real ideal position to mount it. I asked about a dual sensor (one on each side) and neither Roush nor Accel said it would matter. Their point being that if a cylinder isn't working you don't want the controller to try to compensate for it.