just took my 1997 5 door escort gti for its mot, new it was gonna fail as it needs a bit of welding but get a free re test so thought id see what else it needs before work commences lol,

well it failed the emissions and the tester said it could need a new lambda sensor causing high emissions! and also the car if
dle really lumpy then smooth then lumpy on and off all the time?

before i just buy and fit a new sensor is there any other common faults on these that could be the cause to check as well?

thanks marc