look up "M276 Timing chain" videos or "m276 spark plugs. you can do it without removing the air resonator, but i recommend you do it.

 

Thank you so much. Exactly what I was looking for.... M276 intake plenum removal video was it for me.

In case anyone else needs to change sparks plugs / ignition coils....this is how to remove the intake plenum on a GLK350.

 

UPDATE
Finally got around to doing this.....
If you're replacing Ignition Coils or spark plugs A, B, or C (1,2, or 3)....intake plenum removal is not necessary. You only need to remove the air filter housing.
If you're replacing C, D or F (4,5, or 6)....intake plenum removal is required.
Another note: the ignition coil pack part # that I removed is A2769060260. The new part # for this is A2769060501, they are compatible.

NOW ONTO MY "NEW" PROBLEM:
After replacing the ignition coil and putting everything back together....all new problems.
1) it's idling very rough....not steady, up and down, up and down.
2) pressed on the gas pedal (while in Park) hoping to clear the rough idle, no acceleration...if anything the RPM would go down each time I pressed on the pedal.
3) the ESP light warning Inoperative appears on the dash
4) Aux Battery Malfunction warning on the dash

Im hoping that all this sums up to a bad / loose connection. I did double and triple check all the connections I disconnected when removing the plenum...they all seem to be tight.
What am I missing? Any thoughts?

Thanks in advance...

 

I have always repeated the advice to learn how to do the air intake manifold removal. It is not hard, takes 10 extra minutes to do and allows you to inspect many things. It makes servicing the ignition system easier. You can even grab a borescope and inspect the inside of your engine!

Your rough idle has to be the green seals aren't seated correctly. you need to align them on the engine - in the correct orientation, before you put the manifold on.

Not sure what your our lights could be, you need to hook it up to an automotive scanner and read the codes.

 

Thanks for the response...
I suspected the green rubber seals. Was hoping for something simpler like a loose connection.
When I removed the plenum, the green seals were stuck on the underside of the plenum...so I didn't have the benefit of seeing how they were seated before lifting the plenum off.
When I replaced the plenum I put the green seals on the engine. The seals are oval and it appeared there was only one way to seat them...I pushed them all the way down over each engine opening...was this my mistake? Are they supposed to just sit on top of the openings?
Anyone have a photo or diagram of how these green rubber seals are suppose to sit over the openings?

 

I went ahead and removed the intake plenum again today....
And I cleaned up the green rubber plenum gaskets. I placed around the intake openings, BUT this time I did not push them all the way down around the intake opening. On the inside of the gasket w a slight but noticeable lip about midway all the way around the inside. I pushed the gaskets down to this "lip". Buttoned everything back up and (fingers crossed) started it up...........

No improvement. It starts just fine, it idles ok, but the second I press on the accelerator, it bogs down....RPMs drop.

Now...here are my ideas....someone, anyone that has experienced this please chime in.
1). the plenum gaskets are not supposed to be reused, but rather replaced.
2). some sort of throttle sensor went bad ( I don't know if this part exists or if there is one like it but goes by a different name) while the car sat
or
3). the auxiliary battery malfunction warning on the dash persists (this problem did not exist when the car was initially parked 4 weeks ago awaiting the installation of the ignition coil) this is somehow causing the problems

 

Update...

I ordered a set of intake gaskets and installed them.
One of the other problems I was experiencing after replacing the ignition coil was the auxiliary battery malfunction warning...so I removed the battery from the hatch area and
(after reading on the net that these battery tend to drain after sitting for long periods) set it on a trickle charger and replaced it when it was done.
(Side Note: I couldnt find anything on the net about trickle charging these auxiliary batteries...mine charged up just fine.)
I was hoping that the malfunctioning aux. battery was the cause of the "new" problems I was experiencing after replacing the ignition coil. I started it up and no change. The only change was the Aux. battery malfunction light is gone.
Still have a check engine light on
Traction Assist light is on
I can live with dash lights being on...
The biggest problem is...theres no response when I press on the gas pedal. The vehicle does nothing. If I slowly push down on the pedal, the engine feels like it wants to respond like its sputtering just a bit, but for the most part there is no reaction what so ever when I push the gas pedal.
This problem didnt exist prior to replacing the ignition coil. All these "new" problems occurred after replacing the ignition coil.

I'm perplexed! I just dont know what to do other than take it in to the dealer, which I would rather not. Im going to see if I can get my hands on a OBD scanner and check the codes...in the meantime anyone with similar experience that solved this, would love to hear from you.

Thanks everyone for reading.

 

UPDATE...
It's been awhile since I've been on here. The GLK350 is up and running fine. Meant to get back on here to wrap up this thread with the resolution to the issues I was having.
So the solution to all the "new" problems I was having was the connection to the ignition coil that I replaced was loose. I didnt push the plug all the way onto the ignition coil. In my defense, the ignition coil that I replaced was the hardest to get to...near the firewall. Had a hard time fitting my fat hands in to the tiny space.
Thanks for all the responses and I hope what I have learned and posted here helps somone else.