Thread: o2 sensors
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      05-22-2013, 12:46 PM   #6

Drives: 2008 E92 M3 M-DCT & 2017 440GC
Join Date: Dec 2006
Location: Mission Viejo, CA

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Originally Posted by WERKE View Post
Perfect, thank you for the answer. For that is why I want to replace the o2 sensors is that someone on the forum told me to fix a problem with my M3 at low speed (-1500rpm) when I jump on the gas pedal, the car takes some time to react, as if the car hesitated a moment before accelerating. Also, past 6000 rpm, it seems that the strength of the acceleration is less than before, as if to 6000 rpm it had reached its maximum power..someone has suggested that I replace the o2 sensors on the primary catalysts and also replace the spark plugs.

Input is welcome.
The problem you are describing will not be corrected by replacing the O2 sensors. From your description you do not have a check engine light or codes indicating O2 faults. Changing the O2 sensors will make your wallet thinner giving you the feeling that you have fixed the's a brain tease.

Your description could be misfire on acceleration.
The spark plugs might be the cause of power loss on acceleration and during higher rpm. It could be one spark plug or more, but without diagnostic equipment you will just be experimenting with parts. There are other ignition parts that could be faulty also, so the spark plug change won't cure the problem. The voltage required to fire the spark plug on acceleration increases so this can be related to plugs, coils, coil to plug connector insulation (in old cars the plug wires). Because the spark plugs wear out and are the less expensive part they of get changed when looking for an easy cure. The BMW labor for installation on the M3 doesn't make this an easy decision (about 2 hrs. or $300 labor and about $200 parts at dealer price). If you will be changing spark plugs and have the skill / knowledge then trying spark plugs is an easier choice as a test. There are a few related spark plug threads here to review that might help you with the why and how issues also suggestions for locating spark plugs.