By smell and looking at the plugs. I do have an older LM1 but not working right.
The sensor needs to be at least 18" or more upstream from the end of the exhaust or you get reversion showing dead lean, especially at idle. Also no leaky header tubes or gaskets allowed.
If you have the sensor mounted in the collector on an open header, put a collector extension on it. An LM1 is a good unit.
