E63s m157 cutting power after 5k rpms

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May 12, 2026 | 12:23 AM
  #1  
Hello everyone,

I would greatly appreciate any help or insight on this issue because I’m honestly starting to run out of ideas.

I have a 2014 W212 E63 S AMG (M157) with around 64k miles. I’ve owned the car for roughly 10k miles and the maintenance history on the car is extremely solid. I stay on top of service and have not cheaped out on maintenance or repairs.

About 6 months ago, I started noticing the car would suddenly cut power / limit boost around 5k RPM and above. What’s strange is the car feels completely normal below that RPM range. It pulls hard through 1st gear and builds full boost normally, but once I get into the higher RPM range (roughly 5k-7k), it starts feeling sluggish and won’t continue pulling properly.

At first there were no CELs, but I had code:

P227F00

After researching, I suspected a faulty MAP sensor on bank 2 or possibly a wiring issue because the problem was intermittent — some weeks the car felt almost normal, other weeks it would limit power badly. I replaced the suspected map sensor, but the issue remained.

A few months later I then received which through a CEL, But only for about 24 hours and never came back.

P227D

At that point I took the car to a reputable European shop for proper diagnostics. The following was performed:
  • smoke test
  • wiring/voltage testing
  • leak inspection
The shop found no evidence of boost leaks or wiring problems. Since then, I have replaced all 3 MAP sensors with Bosch units and still have absolutely no change.What confuses me is:

the car idles and drives fine otherwise

boost comes on hard initially

issue mainly appears in the upper RPM range under heavier load

sometimes the car will randomly have “good weeks” where it feels much stronger
Because of this, I’m beginning to wonder if this could potentially be fuel related rather than boost leak related possibly HPFP related or another fueling issue that only becomes apparent in the higher RPM range when fuel demand increases.

At this point I’m trying to avoid continuing to throw random parts at the car and would really appreciate any advice from people familiar with the M157 platform or anyone who has experienced something similar. Please ask me any question's if needed! Im Stressed!
Reply 0
May 12, 2026 | 07:32 PM
  #2  
weakness above 3k
Quote: Hello everyone,

I would greatly appreciate any help or insight on this issue because I’m honestly starting to run out of ideas.

I have a 2014 W212 E63 S AMG (M157) with around 64k miles. I’ve owned the car for roughly 10k miles and the maintenance history on the car is extremely solid. I stay on top of service and have not cheaped out on maintenance or repairs.

About 6 months ago, I started noticing the car would suddenly cut power / limit boost around 5k RPM and above. What’s strange is the car feels completely normal below that RPM range. It pulls hard through 1st gear and builds full boost normally, but once I get into the higher RPM range (roughly 5k-7k), it starts feeling sluggish and won’t continue pulling properly.

At first there were no CELs, but I had code:

P227F00

After researching, I suspected a faulty MAP sensor on bank 2 or possibly a wiring issue because the problem was intermittent — some weeks the car felt almost normal, other weeks it would limit power badly. I replaced the suspected map sensor, but the issue remained.

A few months later I then received which through a CEL, But only for about 24 hours and never came back.

P227D

At that point I took the car to a reputable European shop for proper diagnostics. The following was performed:
  • smoke test
  • wiring/voltage testing
  • leak inspection
The shop found no evidence of boost leaks or wiring problems. Since then, I have replaced all 3 MAP sensors with Bosch units and still have absolutely no change.What confuses me is:

the car idles and drives fine otherwise

boost comes on hard initially

issue mainly appears in the upper RPM range under heavier load

sometimes the car will randomly have “good weeks” where it feels much stronger
Because of this, I’m beginning to wonder if this could potentially be fuel related rather than boost leak related possibly HPFP related or another fueling issue that only becomes apparent in the higher RPM range when fuel demand increases.

At this point I’m trying to avoid continuing to throw random parts at the car and would really appreciate any advice from people familiar with the M157 platform or anyone who has experienced something similar. Please ask me any question's if needed! Im Stressed!
> Your No1 guess about fuel delivery is right!
What are your Hi/Lo fuel PRESSURES?


> Running chassis VOLTAGE...:
regulated above 12.6V ??
or below 12.3V ??
CTEK float... great ?


> Next.. confirm your Banks FUEL TRIMS:
LTFT 1+2 at hot idle.


> Beyond that...
whole chassis scan for collateral bus disruptions.

Reply 0
Yesterday | 12:38 AM
  #3  
OP also look long and hard at the charge coolant pump. Intake air temps go way up and what happens? The electronics cut boost to keep it from blowing up. When are charge temps going to be highest? High RPMs with full load.
Reply 0
Yesterday | 02:36 AM
  #4  
Are your intake hoses collapsing or torn?

That was the cause for me to have the car just fall on its face at WOT in 3rd/4th gear.

Was a simple fix and the cheapest one at that. It happened 2x to me, I was happening to be changing the oil that weekend and noticed the hose on the the driver's side was torn when changing the filter.

Completely unrelated this also happened to be on my RX-7 with the intake hoses collapsing under load. Just checking under the hood, the hoses appeared normal, but it was not uncommon on that platform.
Reply 0
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