clio 172 phase 1 idle noise

[grangie]

Ok, got this car today and seemed fine, took it for two test drives before buying, seen it from cold start and running until hot, was all ok.
Only fault i found was slightly lumpy on idle which i had read is quite common so no major problem.
Anyway on getting it home, less than a ten mile drive, it drops to a normal idle and sounds like an old transit diesel engine. Goes away when revved but on idle sounds rough as *&$%!!!
Runs fine when driving, no power loss, only other notable thing is revs sometimes stick when coming off throttle but then a quick tap drops them back down????
Any help appreciated, thanks in advance, Joe

[AlBags]

To start with, you need to check and clean all around the throttle butterfly with carb cleaner. I think these have a common butterfly .. I may be wrong.
Next is to check the tps sensor. It may be giving bad readings with throttle closing.
You may also need the MAF sensor checking. Do that last, if no improvements with the others.