hello wondered if anyone can help. my alfa has failed its mot with very high emission, i think 7% was the reading. It also failed last year for the same but replaced lambda sensor and it passed. This time because my car has never idled right, smells rich and drinks fuel i took advise to replace the mas sensor hoping to solve my problem. No such luck. Car ran fine at idle but, would only rev to 4000 revs when driving, cough and splutter and kick out black smoke.No point retesting this so got it plugged in at garage. Maf sensor and lambda sensor both came up. Didn't want to pile money on new lambda sensor to find this doesn't cure my problem. Engine management light did flick on but has gone out, maybe emissions. Can anyone help. Can't work out why new maf sensor would do this, and if new lambda sensor would right this.