High emissions test readings help
 

Just had MOT done car failed on emissions due to high lambda reading after 2nd idle test and high carbon monoxide reading after 2nd idle test it was way over a hundred.
ive got a 2005 WRX running approx 320 bhp got a sports cat fitted on the downpipe with an after burner backbox with no cat on the mid section. Any idea how to get my readings lower? x

Take it for a good blast before the retest. Get the cst super hot.
I'd remove the air filter for the test too to help more air get in.

Ok thanks I’ll give that ago x

has it passed ? 👍

Do you use it regularly? Is the fuel in it really old?

Car due in for it’s MOT next week was unable to do it recently due to family commitments. Up until about 6 months ago the car was used as a daily driver but then lost my job so only gets used about once a week so perhaps it needs a good run out before MOT and before I remove the air filter. Silly question but is it safe to drive the car without an Ait Filter in?

if it was me , a good run before the mot then see how you go , fuel will be possibly starting to go off, worth filling with some sul , i would always run a car with an air filter , i don’t know how much difference to emissions with no air filter , it should be fine with a filter 👍

I didn't get mine out for any real runs and it really struggled to pass this year.