I been getting randomly misfiring on a 08,528i my car has 101k miles and recently replaced spark plugs but not the coils.
I recently bought an obd2 and scanner and started to use it in the mornings and been getting randomly misfiring on different cylinders and if I run a diagnostic later car will not throw any misfiring. Please advice.
Thank you.

 

Being it looks like the misfires are isolated to cyl 1 and 3, most likely just coils starting to go bad on those two. I just had one go bad on my 2004 with 85k miles. If it were random throughout all cylinders, it'd be something much different. Does it throw a CEL on your dash every morning? Or do you just see this from checking it with the obd2?

 

The weird thing is that sometimes I will get the misfires on a different cylinder, and have not got any engine light come on yet.
I had the rough idle for 2 months with the idle been at 650rpm so I took the car to the dealer and they rise the idle to 750rpm and also had the fuel injector service done at the same time and car has been running better since then except this misfires that started to happen.

 

Maybe you have the same problem I had? https://5series.net/forums/e60-discu...ortant-128827/

I was getting random misfires, O2 errors, all sorts of things. I don't know if it was just in teh AM since the mechanic scanned it at night when it was warm. The only thing that showed in my dash was "Increased Emissions"

 

Check the "electrical wires" that are connected to the ignition coil "connectors". Someone might have broke the "insulators" of the wires when he/she pulled it out of the ignition coils.

Good luck.