To All,
I recently replaced the 6 plugs in my 2010 GLK350 4Matic and all was going well until idle. I have noticed a slight hesitation that cause the engine to jerk as well as you can hear it in the exhaust as well. I did not gap the plugs as they were "Factory Gapped" in the box from Bosch. I verified that every plug part number matched the plug I was removing as well. I did verify that I put the air cover back on properly as to not cover the air intake since I have had that issue in the past as well. The vehicle was running just fine before the plug change. I only did the change because I spoke to a MB Technician and he said it is a good idea to change them at 60K and I had hoped for a little better mileage out of the vehicle. Any assistance you can give would be greatly appreciated.

Thank you.

 

Well since I received no answers I took it upon myself to get them. The issue was that Advance Auto says the OEM replacement plugs are the platinum iridium plugs. They are not, you must pay attention to your VIN to see what is required. My model requires the NGK standard platinum plugs and also must be torqued to proper requirement. Hope this is helpful to someone when they go to change their own.

 

testing sig in the test forum