Small misfire on W202 C280 (V6)

[Lilly]

Hi,
I wonder if somebody can point me in the right direction...
I have a 1999 W202 C280 (120,000 mls) with the new (was then!) V6. Lovely car, but have noticed over the past few weeks on idle and cold running, the engine seems a little "lumpy", as if one of the cylinders isn't firing properly. The plugs were changed about 30,000 ago. Is it time for a new set, or should I be looking at the HT leads etc? If I took it to a dealer, or an independant witha STAR machine, could they tell which cylinder isn't firing properly?
Thanks in advance.

 

[piestore]

missfire

hi

yes a star machine will tell you which cylinder is giving the trouble, plugs are probably not due yet but at 30k it won't hurt to change them (might hurt your wallet a bit) but plug caps and leads are a common fault on this engine. if the missfire is logged on all cylinders another likley cause is air mass meter