Please recommend a vendor to clone/replace my ECU
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
O2 cats misfires
The misfire symptoms you're seeing, that get worse upon high demand/acceleration and resolve at low/idle rpms, could be caused by a clogged catalytic converter.
Easy test is to remove the upstream O2 sensor.
When my car did the same thing yours is doing, I removed the O2 sensor and the car ran down the street like a very loud scalded dog.
Put the O2 sensor back, symptoms returned.
Replaced the cats and it was smooth sailing...
Easy test is to remove the upstream O2 sensor.
When my car did the same thing yours is doing, I removed the O2 sensor and the car ran down the street like a very loud scalded dog.
Put the O2 sensor back, symptoms returned.
Replaced the cats and it was smooth sailing...
What engine was that?
Last edited by CaliBenzDriver; Jun 6, 2025 at 12:37 PM.
