I think you are on the right track, we almost see the light through the tunnel, hang on tight. It is a great car overall and which meets your needs. I think it will be worth it in the end.

 

Getting the car back today… unfortunately the driveability issue remains.

I had the exact same symptoms as describe in the AMGMeister video so I was hopeful swapping all the O2 sensors would fix it, but no.

Before that, they also took apart the intake manifold and cleaned out oil and build up on the throttle bodies also.

This shop has had it for 2 weeks now so I’m picking it up for the long weekend to maybe figure it out myself… I’m hoping at this point there is something simple to replace or something electronic to reset.

What’s interesting is when they disconnected a fuel injector, the stumble was gone.

 

HMMMM

 

which fuel injector -'or are you saying when any one injector was disconnected then the stumble went away?

the fuel rail pressures were all copacetic correct?

 

If I recall correctly, they said cylinder 5 which would be in bank 2. The shop mentioned that effectively forces a specific fuel trim on the bank.

BUT the cylinder 7 misfires were still happening.

At this point I don’t really know if I should fully trust the shop though. When I drove it home today, the hesitation and lurching was very noticeably improved, but still happening under low rpm occasionally and up slight inclines with low rpm especially. Although that was after I reset the fuel adaptations again to just be sure. As I went on a much longer and mixed condition drive than I’m sure they did during their test drives.

 

not sure if we asked this yet but did you try another shop?

 

I've had it at 3 different shops now. The first one was a Merc specialist although it was mostly there to take care of preventative maintenance items, camshaft phaser rebuilds, head bolts, tappets, etc.

2nd shop was mainly a waste of time, took it there specifically for a smoke test. Ended up getting bad data from half-assed borescopes, leakdown, and compression testing.

3rd shop was pretty decent but I feel like I ended up wasting time there overall. They had it 2 weeks and most of the promising results came from tests and parts I specifically prompted them to do and replace.

I wanted to take it back to the first Mercedes specific shop before. But for one, they're about an hour drive away from me; and two, they wouldn't response to my follow-up texts or calls.

I'm going to do some more data logging this long memorial day weekend of the fuel trims and camshaft angles. And whatever else I find. I just figured it would be best to take back into my hands as I've already spent way too much on labor at this point to still not have my issue fixed.

I still feel somewhat okay considering the data doesn't show anything catastrophic wrong with the engine and all the parts I've had replaced definitely needed to be replaced, were regular maintenance items, or were common failure points on these platforms.

 

My apologies maybe you did mention it. I am not good at keeping up with things and my thinking is rather slow, sorry about that. Ugh you are so close to getting it too, don't give up.

 

Thanks for the encouragement. It's a long thread, I don't blame you.. And yes, as much as part of me wants to give up, I know I have to be close... and I'm too deep to give up now

 

You got this! All the best buddy. I am not sure if you should find yet another shop but it does sound tiring : (

I mean, you sound exhausted.

 

you could have a leaky fuel injector. It's a BMW thing.. swivel the rail with the injectors out so you can see them all and I check for leaks that way

this is such a nightmare, I'm happy in non-AMG land for the forseeable future after I got rid of the GTS

 

I was happy in Porsche land but I had an itch for a big NA V8 that wasn’t some American boat

But anyways, I’ve already swapped all the fuel injectors with new parts. Same issue before and after. Today I also disconnected all the injector connectors on bank 2 along with the MAF connector, camshaft solenoid connectors, and fuel rail connector. Cleaned them with electrical connector cleaner, issue still remained a bit. (Although it could’ve been the car still adapting, albeit unlikely)

The one drive I went on today after I reset fuel adaptations, I wasn’t logging. I may get out again tomorrow specifically for testing to log camshaft positions, cylinder faults, etc etc.

To be fair to the M156, this doesn’t seem like a common issue and most common issues are well documented with fixes. I guess I’m just unlucky

 

For sure, the V8 is a very rewarding engine, a charismatic engine actually, this is so far a bumpy ride but you will eventually reach your destination, just never give up. Sorry again that you have to deal with this, hopefully you get it figured out very soon. You have the support of all forum members in this thread. You are not alone on this, best of luck OP.

 

I had a 997. Probably the best most reliable car I owned. Where it killed me was the parts cost on the thing and all the stupid "while youre in there upgrades", the Porsche tax is SO brutal unless youre me with a toolbox, lift, shop, technician, free time to be on the internet all day, the thing just consumes your life. I also don't think their owners club is particularly fun to hang out with nor can they drive very quickly. It's a glorified parade.

1. $500 clutch kit, does not include flywheel, its like $200 for clutch AND flywheel on a C6 corvette, if you upgrade its like $2400. Theres a fun hack where you use an Audi A6's friction disc and its a huge upgrade.
2. Struts are $200-300 EACH. Does not include mounts, boots, and safety hazard of disassembling a strut.
3. $700 brake kit, they're smaller than an S Class where you can buy Pagid for like $80 a disc and pads for $50 from Brembo/Ate/Ferodo. If you switch to Akebono its buy once-cry once.
4. Meyle is considered an awful brand but the only available control arms are the $200/corner Meyle HD
5. Transmission mount tool is a glorified bushing press tool and its $200
6. The dreaded oil separator + oil cooler replacement

Then we get into the aftermarket stuff to fix things

I have a $1500 shifter + cables on it cuz the thing is so notchy and shifter is so loose it feels dangerous
Momo wheel plus adapter, the stock wheel feels weird
Stock struts are so expensive its cheaper to go coilovers, so Feal 441 just to save money
I have to re-do the LN Engineering IMS bearing every clutch change so every 50k is an extra like $1000 and you have to pay an authorized dealer otherwise there is no warranty, I am not LN approved and I don't care to be.. I discovered the Pelican Parts kit afterwards for $200
$230 Rennline bump steer kit, I don't mind the bump steering TBH but its a must-do

The GOOD:

1. The heater core involves removing your battery and replacing the hoses and the heater core, its a 1-hr job. It's 20 on most cars.
2. The OE German TRW (now purchased by Lemforder and Turkish garbage) control arms do not have a lifespan, I've seen them last 150k+ miles
3. Transmission removal is only 2 hours for me.
4. Oil pan reseal is a BREEZE.
5. Annual filter/oil change is a breeze. The cabin filter is legitimately 2 minutes, the air filter is about 5, and the oil can be drained without a jack if youre good.

You're super unlucky with the M156. I think your issues don't sound motor specific though. This is probably one of the worst ones I've ever seen.

 

Good lord I can hear the maintenance trauma haha… Definitely agree on the Porsche tax. I had a 958 Cayenne S and 987.2 PDK Cayman.

Got rid of both roughly around the same time for family needs. But that generation Cayenne S is such an all around great vehicle. Off-road capable, very smooth and comfortable ride. The 4.8L V8 is enough power and feels great down low. Lots of parts sharing with Audi and VW so parts aren’t crazy.

But yeah the 997 IMS bearing is a scary point on the non Turbo engines. The Cayman engines are a bit more serviceable in comparison as you have essentially 3 relatively easy planes of access through the top access panel, there’s another interior access panel behind the seats, and of course from the under bay. Not much power short of the GTS models but it’s like a Miata in a suit.

 

Ah yes, Porsche tax is discouragement for many

For me main problem was the seats, I can never find porsche seats comfortable, I have a bad back. Pretty sure not a lot of people suffer from this so that is good.

 

Another thing is I like to daily drive my cars, not a fan of garage queens, so I prefer a vehicle I can drive in the snow as well, people probably will yell at me for driving a 911 in the snow porsche fans will call me an abuser.

 

Yeah I mean I work in fine dining and I enjoy my food so the Mercedes life is the life for me after a big stupid meal or a night at the restaurant. That and $20 sway bar links, $60 Delphi control arms, $7 fleece oil filters, and 400hp with a OETune Stage 1 tune with 50tq over stock where I can appreciate it.

The only thing I have to do is buy a few hundred dollars in parts off Rockauto a year and I get to drive a big stupid Mercedes that MB themselves couldn't afford to reproduce in today's age. The thing that annoys me about Mercedes is just about every single Mercedes I've ever driven has startup chain slap from the tensioner.. even the G550, and GTS. I've learned to ignore them all.

I think Porsche is the superior brand for absolute quality but I think a fast car is easier than a truly NICE car to make and I think I aged out of the Porsche demographic (I'm 37). I just like to slink into the S or E after a long day and melt into the seats for 10 minutes before I even set off.

 

You can't get a V8 in a 911 though : (

 

no but you don't need a v8 when the car weighs 1200lbs less LOL

I will say after all my seat time in the various AMGs over the years in the shop, an AMG is more fun when youre doing nothing. You gotta be really involved to wring out a Porsche which is a good thing if youre into it into it, but even doing 70mph down the freeway an E63 is a helluva experience.

I will take the awful mid-tier v6/v8 non-AMGs though so I don't end up like Zack over here (im kidding). I also like to drive drive so I like to wring an engine out, I love the 420/430/43/400/550/500's for this reason. I think the GLE43/ML400/E400/C450 might be the best not under or overwhelming cars MB makes

 

It is hard to explain, the 6 in the porsche is a scream, the V8 in an AMG is a growl or roar. Different beast : )

 

Okay guys I really don’t need any more convincing to switch back to Porsche

Although the 2018+ Cayenne Turbo will almost certainly be my next 4 door, that is a few years down the road once I have some kids leave the nest. Then an Audi R8 for weekends! Easy 2 car combo for everything that doesn’t break the bank /thread

 

Fair to say I was the one that said AMG V8 is better.

 

Okay! Actually getting back on topic, for real this time.

So I went on a proper test drive today and hooned on it a bit.

First of all, it feels great. Very healthy horses under the hood (most of the time). I logged fault counters on about a 20 min drive of mixed driving. I still am seeing some faults on cylinder 7, but I only saw them go up to 5 as most. Previously we were seeing 50-70 spikes. So something is definitely better than before.

Now here’s where things really getting exciting! I finally have a CEL! Now I find this hilarious because normally people would not be excited about a CEL, but I’ve been in the dark this whole time. And it is actually pretty in-line with some evidence we’ve been seeing and in correlation with AMGMeister’s video.

Codes 0578 and 2197. “Oxygen sensor 1 (cylinder bank 2) has an electrical fault.”

Now what’s somewhat perplexing is that this is after I had all the O2 sensors replaced. So intuitively I’m thinking there must be some wiring fault to the sensors, but I’ve yet to research these exact codes. And yes, I’ve cleared them and they both reappeared.

 

Do you think the fore and aft O2 sensors could be swapped? Cracked bung? Not installed correctly/crossthreaded? It's the correct Bosch one yea I mean you've been pretty good about parts so far..