Hi, have a 2014 E350 4MATIC, after a hard acceleration by a co-worker in sport mode, the car threw a flashing engine light with it running ruff 10 minutes later then disappeared in about 20-30sec. ECO mode was automatically switched off and could not be reactivated. After letting the car sit for about 3 minutes, and restarting it, the eco mode worked as normal. I’m assuming it has something to to with the spark plugs as a flashing engine light symbolizes a cylinder misfire, my assumption is it seems like the previous owner never did them at the interval of 100,000km looking back at the old service records. The car now has 122,800km roughly.

This morning my family member attempted to start the vehicle, but only cranked, took a few tries for it to start, but did eventually, now starts perfectly fine like normal. Slight rough idle.

Anyone else have this issue?

 

Ran a scanner, with icarsoft and clicked read codes, and there were none. Battery was replaced recently so definitely not that.

 

ISTR that the 3.5L engine is notorious for eating the spark plug electrodes. Pull one and check it, or just take it to the dealer and have them all replaced since they're past due anyway.

 

Did you get the issue fixed. I just had the same problem today after driving in for a few miles in sports mode

 

Just a quick adage to the emissions related engine light.
a check engine light that is in solid, vehicle is safe to drive.
A flashing check engine light, pull over and shut down. Call a tow truck.

In my experience, a flashing CEL is usually the result of catalyst overheat. This could be from broken media blocking the stream of exhaust or the media being clogged. In either case cat temps skyrocket and your 02 sensors report that as overheat.

That being said, I have been in the auto industry for a while. Mostly domestic and some Italian. In those cases, I've always been told to get the car safely off the road and call a tow service. I can only assume that German cars are the same because their emissions systems have to report the same info as all other car makers in the US market.