had boost issues with this car for 8 months now and i am beggining to loose patience with it. its just isnt running correctly. its like there is to much boost for the revs. anyway i had a fault code of 16804 come up (bank 1 oxygen sensor below threshold) so i have replaced the "pre" cat lambda. i have had the second lambda reprogrammed at amd a few weeks back as it has a decat. and 3 days later after having replaced the "pre" cat lambda with a bosch one, the same fault code appears agian. what else could it be???