97 saxo vts emissions

[pearl nicholas]

failed the emissions on lambda reading after second test,took to a local well known tuning place and read the fault codes,map sensor and coolant temp sensor replaced,car basically the same,it starts and runs fine when cold but as it starts to warm up the idle becomes erratic,the rev counter doesnt dance around possibly because the hunting is too fast,anyone know any other problem areas on these?
was wondering if the cat may have been gummed up by possible constant over fuelling

[trickywoo]

Surprised they did'nt change the O2 sensor thats often the route of lambda issues.

If it failed but ran well the cat could be the issue but the poor running would not be caused by the cat (unless it was seriously FUBAR).

Could be an air leak induction side.

[dain bramaged]

lambda fault could be down to a faulty sensor or exhaust gas leak as it reads the level of oxegen in the exhaust and controls the fueling to suit,
if the car keeps cutting out or has an idle fault could be a problem with idle air control valve or the throttle housing might need cleaning out you can also try disconecting the battery to clear the fault memory and give it a good blast up a bypass

[MEGAMANIAC]

Have the injectors tested they are prone to faiure,also as said blow on the exhaust ,is it on standard air box i have had problems with one's not standard

[pearl nicholas]

its on an induction kit which doesnt help,i replaced the cat yesterday as it was holed on a joint weld but now am having trouble sealing the exhaust back up,the cat isnt a dealer part and is not a perfect fit,will have another go on the weekend