On a recent trip to the mountains my LX470 did not want to accelerate/shift up to third gear up to third gear while ascending. Even when flooring the gas pedal the engine reves up to over 3000 rpm but fails to shift up to third gear which would allow me to accelerate. I tried letting off the gas to allow it to up shift, but still it would not. It only happened on the under 65 mph above 45mph mountain roads. My check engine light is one due to either a bad MAF or O2 sensor. The car drives fine around town and perfect in cruise control on interstate at all speeds.
Could this be a transmission mechanical issue, electronic/computer input issue or o2 sensor issue?
thanks in advance