W124 Ignition coils

[GP801]

Our 1995 S124 280 seems to have a real appetite for ignition coils. It has had 2 complete sets in the last 4 years. The latter set in october 2008 were genuine mercedes fitted by a main agent in France.(Dont know origin of the others) In Jan 2010 it had number 3/4 replaced to sort out a misfire and it has now just had the same one replaced again for a misfire. Is this unusual? Are there any underlying causes to look for. Wiring loom was replaced september 2008. It has done 132,000 miles.
Any advice welcome. Thanks
Nigel

 

[grober]

Are you sure the problem is not with the "extenders" item 8 and 89 here [part listing is innaccurate] or other parts of the high tension leads. çàï÷àñòè Mercedes: êîäû çàï÷àñòåé ìåðñåäåñ

You say the engine wiring loom was renewed in 2008 but sometimes odd components are not included??? I hope you insisted that MB parts were used thro-out since pattern parts are known to cause problems. Are you using the correct grade of spark plug? I tend to favour NGK nowadays since I feel their quality is more consistent then Bosch.

 

[GP801]

Thanks.Loom was genuine mercedes - I have receipt. Plugs genuine mercedes. Coil packs were genuine and as far as I can tell extenders were changed aswell - the invoice is in french but from main agent. Local dealer can find no other issues. In fact mercedes local dealer is going to put this thru as goodwill/parts warranty as they feel should not have failed so soon.