Intermittent Misfire on my 325i Coupe with n N52 Engine

Hi All,

So I have experience this this issue for a few months now.
The initial Diagnostics pointed to bad Coil Packs 1&2. I replace all 6 with OEM Coilpacks. 2 days later the misfire was back. Did another Diagnostics and this time it pointed to Post Cat Sensor in active. Replaced this sensor and the problem was still there but this time diagnostics pointed to Bank 1 Sensor 2. Replace that and 2 days later it started the misfire again. Did another Diagnostics and this time the fault was Fuelsys1 02Sensor OL. I started by cleaning the DME. Then the fault was only in the mornings. Please can I get an insight into this issue.

Check the catalytic converter backpressure, clogged cats can cause misfire.

Have you done a compression test?

if the fault seems to be limited only to the mornings, this could be temp related, morning temps are lower than later on and therefore temp can cause issues if sensors are cold, especially the post-cat sensor and bank 1 sensor 2.

Did you replace spark plugs along with the coil packs ?

This bra joined the forum to ask questions, and left it when he got answers.