2016 Dodge Journey stuck in limp mode

My 2016 journey with 25000 miles seems to stay in limp mode. Very slow pickup and will not downshift when stepping on the gas. Have had it back to dealer twice with no fix. The third time the check engine light came on. It showed an oil senser needed to be replaced. The check engine light is now out but it still will not downshift when stepping down on the gas pedal.Does anyone know what gives?

The dealer’s mechanics have actually had their hands and their instruments ON the vehicle and can’t fix it. I can’t see, hear or touch it so the only help I can offer is take it to a better dealer. Yours is not very good.