Ougoboy

97 E420, 140K Random Multiple Misfire / Cyl 5,6,7 Misfire, Replaced 2 coils
Replaced Plugs(NGK Platinum) Problem still there, Replaced Mass Air(Salvage Yard) Idles better still has misfires ??

Thanks In Advance

BJW

anesh01

Try replacing the spark plug wires, i had the same problem,changed the coils, plugs, and finally the wires, and it worked....hope that helps in any way

Fabio D

The E420 210 not comes with spark plug wires.. they have8 coils insert direct to the spark.. i'm pretty sure you have a bad head cover gasket & you get oil inside the spark site. try to check. if you have oil cange the gasket clean all the oil with some "thiner" & clean too the rubber part of the coils (maybe you need to replace the "8" rubber conductor by the coils) is pretty common this fails in te M119 updated engines

Other way, try cleaning the fuel injectors too (common issue in the m119)

Fabio Daniel

Ougoboy

Hey anesh01,Fabio D,

Thanks for the reply, Yeah I have 8 coils, There is no oil down in the wells,
I checked for that first, Driver Info center Says Check Engine Electronics, Guess I'll look into the injectors

ohlord

platinum plugs on the 420 or the M104 copper plugs is what they likes.
Also you replace the connectors when you do the plugs.
Beru (OES)
Spark Plug Connector; Between Coil and Spark Plug
For models with distributorless ignition, having individual coils for each cylinder. 1 per cylinder.
$14 at autohausaz.com common issue on the m119

Fabio D

Correct! thats what i'm talking about. Spark plug connector (Coil conductor rubber) is a common issue in the M119's with missfire, but some cases in our workshop fix it with a fuel injector cleaning/change the 8 little filters & seals..
Try cleaning it first. hope you solve the missfire

Fabio Daniel