New codes up P1128 P0446
 

Evap emissions systems Vent control?

could this be overfilling the gas tank or possibly the fuel cap?

P1128 Oxygen Sensor.
How hard is this to change?

The O2 sensor can be changed by any exhaust shop in about 15 minutes if you bring the part. Most of the time is waiting for the exhaust system to cool down. Takes a special tool.

Don't buy generic ones or ones without crimped on at the factory pigtails.

Bosch makes the parts for Porsche and they can be had for less without the Porsche label stenciled on. I used two Bosch. More info including part numbers here.

Thank you appreciate it

Thanks for the Link - Nice info to bookmark - Rick

P0446 is evap canister shutoff valve (function) below limit. Possible causes purge air line blocked
Evap canister purge valve stuck in open position
Evap canister shutoff valve stuck in open position or blocked
Flow in evap canister too high (filter deformed blocked)
Pressure sensor connected incorrectly (polarity reversed)

P1128 360 Oxygen Sensing Adaptation, Idle Range, Bank 1- below limit
Possible fault causes
incorrect signal from the MAF sensor
fuel pressure too high
fuel injector leaking
EVAP cannister Purge valve open

Check signal from MAF sensor
Check fuel pressure
check fuel pressure regulator, vacuum connection and fuel return line
Check EVAP cannister Purge valve
Check fuel injectors for leaks

As you have both the P0466 and the P1128, and both of these codes appear with the EVAP cannister purge valve open, first thing I'd do is go take a look at that valve.

Replacing an O2 sensor is not even in the troubleshooting, so I'd stay away from that.