hey people
been on here alot and found it useful and thought it was about time i joined
ive got a w reg mk2 punto sporting and its just failed its MOT on the exhaust emissions. on the fast idle test it passed ok but on normal idle its failed on co levels. its had a reading of 0.71%.

i bought it in may and since then its always been lumpy on start up and at idle and until its been run for 15mins or so it misfires and runs lumpy around 3500rpm. theres only 1 modification made to the car which is a centre exhaust which came with the car.
looking through the history its had its headgasket done in march so just wondering if this wasnt done propperly might cause the high co levels??

has everyone else have any ideas how to cut emission?????
thanks

I'd try putting some red-x or similar into a tank of posh petrol and giving it a good motorway blast then take it back to garage and try again. Just make sure the car is nice and hot before going back for retest.

yh i was told about the fuel additive. it had a good motor blast on the weekend, from boston to huddersfield lol, but it still runs lumpy and has a habit of stalling at junctions

Scroll down half the page:
https://www.fiatforum.com/punto/277999-passed-mot.html

ive read the tread thanks.
before i took it to the mot center i was running about in the car for about 45min, which should b plenty of time for the cat to warm up??

but the cat wouldnt be the reason why the engine runs lumpy at idle which i think is the reason why it failed to emissions. would it be worth changing the plugs???

Tickover wont produce enough gas flow to do the job properly. Mush better to drive the car at speed for a good distance.

Lumpy idle indicates the ignition and/or fuelling need work. It will be putting unburnt fuel down the exhaust which the catalyst has to deal with. There are lots of threads on the subject. You will need to do some google and forum searches