SeanMGibson1835

2 Days ago I Installed 6 brand new double platinum spark plugs in my 2011 MB C300 with the 3.0 engine. After installing the new plugs I started up the vehicle and it was running very rough. I turned it off and restarted it and it was fine. Driving around I encountered no issues. Now today it's running rough again and RPMs are going between 500 and 1,000 at idle in drive and in park. I took the cover and packs back off, checked all plugs and made sure they were torqued down to spec. Engine codes came up as "too rich in banks one and two" Has anyone else experienced something similar who can offer some incite?

tekfoc

sounds like a bad plug .
even new plugs can be bad

SeanMGibson1835

That might be it. I'll need to replace them again and see what happens. Thank you.

tekfoc

no problem .
good luck

SeanMGibson1835

After cleaning the MAF sensor the problem has been resolved. I used K&N filters so make sure anyone using these filters takes the time to ensure they are not over oiled. These particular ones were overoiled from the factory.

JohnnyC

This just reinforces my fear of K&N stuff.

gamma300C

For years there have been articles talking about how K&N filters' increased airflow has no benefit for the average stock motor and how they let in more dirt and lead to piston/cylinder wear. Good only for high volumetric race engines that get rebuilt every season or sooner.

SeanMGibson1835

Yeah, the engines need to be tuned in order to maximize the efficiency the K&N filter.

Hrvat9

I’m going through the exact same thing. Replaced wit new Bosch and now I’m running rich at bank 1 and 2