Don't believe the tank pressure sensor as a fault. If that was an issue you would have an EVAP code as well as a throttle position code. AutoZone LOVES to sell parts.
From the codes you posted I would check the wiring at the TPS sensor at the throttle body, as well as testing, or just replacing the TPS sensor. Setting for long periods of time can easily create corrosion. I would remove the connector and spray a bit of contact cleaner in the wire side, then plug it in/out a couple times. The TPS only uses a 5 volt signal so even a small amount of corrosion could cause a voltage issue.
That could cause the shifting issue because the PCM uses throttle position as an input for gear selection and shifting points.
However it's also possible the shift issue is mechanical and also due to it setting for long periods. I would deal with the TPS code first.
Tuesday, January 30th, 2018 AT 10:03 PM