Helping a friend out with his v8 petrol.. his cars idle is running low and it's sometimes cutting out after it's been started then it performs fine... it's giving a lambda fault on bank 1 ... not sure if related but he let his fuel run really low yesterday then filled up with bp instead of the usual v power? Maybe coincidental but wondering if the empty tank has contributed?

Reset the code run it for a week see if it returns

Yeah did that straight after it threw the code..cars behaved all day so wondering if it's been the fuel filter or some sort of blockage from low fuel in tank?