MoTeC LTCN - Manual (Page 26)

26 Operation
LTC Operating Tips
If the engine misfires for any reason, including an over-rich mixture, the LTC
may falsely read Lean. This is due to excess air being present in the exhaust
gasses, caused by incomplete combustion.
Other areas that can give misleading readings include at high RPM, closed
throttle when the mixture won’t burn completely. Following overrun fuel cut
when the sensor has become saturated with oxygen it can take up to several
seconds to resume accurate readings. Engine misfires include hitting the rev-
limiter, be it a fuel or ignition cut or a combination of both, and can give a
similar result with time being required to purge the sensor of excess oxygen or
fuel.
Engines with high overlap camshafts running at low speed may pump air
through the engine resulting in a false lean reading, Therefore the LTC may
need to read leaner than would otherwise be expected.