frogger42

Lately, my 550 has been doing the weirdest thing after more than 30 minutes driving it freeway speeds. If I slow down the engine feels choked and it starts rumbling and then it flashes a check engine light if I turn my car off and wait 10 to 15 seconds and turn it back on the light goes away and the engine runs normally, below is the one of the codes that I see from the scan any ideas what this is?

silvergl

I have no idea other than the code. But lugs and coils are cheap. You could even swap them with a other cylinder to see if the code moves too.
that's how I would start

rapidoxidation

Guessing that a coil is getting heat soaked and starting to fail. Like silvergl says, swap the coil with another cylinder and see if the code moves with it.

frogger42

Thanks all while I’m there does it make sense to try to replace the spark plug or is that entirely independent?

I’ll report back with findings!

silvergl

I would replace the plug and coil, probably about $100. in my opinion, if I am going to remove something i generally put in a new one.

frogger42

went ahead and replaced coil #2 and air filters, did the trick. Totally got rid of harsh idle, like new now!!!! I was also surprised at how relatively easy the replacement was. Still dont understand why all the wiring connectors are so darned frustrating to undo.

chassis

Next step is to replace the 7 other plugs and coils.

L&N Caravan

which vendor was selected to supply coil and plug? Any other peripheral parts/pieces that would need replacing were process to be done again? Mine are coming up as well and need to prepare, thank you.

frogger42

rock auto. Went with Bosch coil and plug. Hengst filters. Need ratchet extension and universal joints.

also need 14mm plug socket and e8 star socket for coil screws. Also want some dielectric grease.

lisle 51410 pliers really help with coil pack removal.

frogger42

unfortunately our hood area is slightly less generous than the s class.

L&N Caravan

Thank you frogger42, on both counts!