I own a 2015 E350 4matic Sport Wagon. It currently has 102,200 miles on the odometer. About three weeks ago the "check engine" light came on and the car wen into what I will describe as "limp mode". It became very sluggish and seemed to be not running on all cylinders. I pulled into a parking lot after about 1/4 mile and shut the car off. After 2 minutes I started back up and the "check engine " light was off and again running normally. This happened three other times in the following weeks.

I set up a service appointment at my "local" (about 50 miles) Mercedes dealer. They hooked the car up to diagnostics and did not find any codes stored. I had planned to have a lot of services performed: cooling system flush, brake fluid flush, trans service, spark plug change, replace battery, steering rack recall, oil seepage at front valve covers and the B-Service.

Being as there were no codes and the no record of the spark plugs having ever been changed, the technician stated that the engine may have been missing due to worn out spark plugs. It seemed reasonable to me at over 100,000 miles potentially on the original plugs.

The work was done over two days and I went to pick up my car. Driving home was fine, no problems. The next day, I drove to the P.O., about two miles one way and on the trip back the check engine light comes on again and the car goes into what feels like "limp mode" again!

WHAT do you all think should be looked at IF there are STILL no codes recorded in the computer on this car?

Thanks for any and all help in advance.

dave

Read it while it is on and it get you enough info to start troubleshooting. Plugs may well be issue if original and tech should be able to tell when they are removed. You will need to read code while it on to tell what actual fault is.

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Jim

Thanks. I was not aware that codes were not recorded and stored for later analysis.

With the right code reader it will read codes that have been there and then gone. It will be indicated as a "stored" code.

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Jim

It's hard to believe that the dealer can't pull stored codes. The plugs on the 276 are due at 60k or ten years. Sounds like a run of the mill random misfire. I pull stored codes on these all of the time with my Xentry. It's never the plugs. Usually it's a bad coil or cheap Costco gas.

Oh no.

The wife had a birthday earlier this month and I took her and signed up at the Costco about 60 miles away. We filled the GLK up with the Costco gas. I hate to hear it is no good but she did enjoy spending her birthday Costco. I got her a couple of new tires for but not from Costco for her birthday too.

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Jim

Yeah. Whenever we get cars that are misfiring due to contaminated fuel, It's always Costco or Safeway gas. We had a m112 a while back that backfired and blew the intake apart. When we took a fuel sample, I couldn't believe how much water was in it.