[JLMounce]

I believe these units show commanded duty cycle. They rely on the wideband o2 to determine if what is being commanded is actually happening.

Here's the ****ty part of that equation. There's only a single sensor and it's usually on a single bank. If you have an issue like what gman005 had and it's occurring on the bank that isn't being monitored by the o2, all kinds of stuff can happen.

If a dual plane manifold is being used, the effect is somewhat less since opposing cylinders will typically be seeing the same throttle bore. If a single plane is used though, you get a couple dead holes at best, or a couple insanely lean holes at worse.