Petrol smell

[Burgerman]

Hi all , can anyone give me any advice,

I have a Toyota Yaris (2000)

on initial start up the smell of petrol is really strong,  it like the automatic choke is on and to much fuel going through.

I do have a fault code which is running lean bank 1 . which I believe is down to the lambda sensor.

I had a new exhaust fitted last week now when the car is ticking over the revs keep dropping as if its going to cut out but then comes back to life.

Any ideas appreciated 😁