the shifter gets hot when the car is in neutral or park and not moving, as the shift lock solenoid is recieving 12V, and all that heat goes directly to the steel shaft under the knob. if yours got hot while the car was in motion, then something else is causing it to heat up. its not directly connected to the transmission, but it is fairly close to the heater core.
you should only be concerned if the temp guage on the dash shows above center, as that shows the coolant temp, which is cooled by the radiator, and attatched physically to the transmission fluid cooler.
replace the spark plugs too, as running them with a bad O2 sensor generally fouls them up. i would also relpace the fuel pump and DME relays, the contacts on them probably look pretty shot after 160K miles. lifespan on an O2 sensor in our cars before it starts to cause drivability problems is about 60K miles. they should be replaced in pairs. the boot after the MAF causing a vacuum leak will cause VERY lean running and could throw an O2 sensor code, so fix that first and i will expect the O2 error to go away. however, running the O2 sensors lean until the car dies will probably **** em up anway, so do replace them.
have you had trans fluid service in the last 50K miles? if not, do it now, use Dextron 3 or better (redline D4 recommended)
Alusil, Dinan DME | ITG Air Filter | Eibach/Bilstein HD | 26/20 Swaybars | Iridium plugs | Depo/ProLumen HID | Optima batt. | no AC | Stoptech brake lines, Frozen rotors, brass bushings, Superblue