Hey all,

I just picked my SS (77k miles) up from the dealership after getting a valve cylanoid replaced due to a Large EVAP leak. while there the dealership did not find any other codes based on some other symptoms I had described. After driving a couple mile down the road, stopping in at Home Depot and then taking off again, my check engine light has come back on. This time its a P0135, front O2 sensor.

After the EVAP leak light came on and prior to taking it in, I noticed when my car was started hot, especially on hot days (90*-100* ambient Temp.) the car misfires horribly for 45 seconds or so before it smooths out.

I guess my questions are:
Who has experience with this code/sensor?
Is it pretty common for it go out at this stage in the car's life?
I'm pretty much looking at just replacing the sensor I assume, not much else it could be (obviously wires, but how common is that?)
Could this bad O2 sensor cause the misfires I'm describing above?
How tough is this to replace myself?
It looks hard to get to, any tips on getting it out and the new one in?

Thanks a ton guys!