Good lady's Punto has been off the road for a couple of months now. Went to get it MOT'd, but car was running like a dog. Could only make it up to about 63mph, foot to floor in 5th, and it felt like it was holding itself back. Car felt like my old Fiesta from years back if manual choke had been left open for too long. Got car back (failed on emmisions) and serviced car. All 4 old plugs were showing black 'soot'. Now when car starts, it is obviously not running well, like its missing. Anyone have any ideas? Frightened to take car any distance in case of cat damage due to unburnt fuel.
Cheers!

Graham

Take it the spark plugs were changed if they were showing 'black soot' and an oil /oil filter changed carried out when it was serviced?

I'd consider getting some new ignition leads (under £10 from Halfords) if the car sounds like it's misfiring, my 55S had similar problems that were solved by changing the sparks and leads with the car holding itself back in 4th/5th, though it was happy getting up to 80 but sounded a bit rough.

Might be worthwhile getting a new air filter (again a few quid from Halfords) and seeing if that helps (though filter is generally changed at service too).

If the above things have been tried/done without success, then I haven't got any other ideas, though I'm sure others will!

goood idea what guy above said about air filter, blocked air filter mean less air and to much fuel being burned