head scratcher

[harry007]

i have a 2013 m5 lci.

going back a few months, sometimes early morning start the car would idle funny for a second or two and then fine.

the car is standard, just has catback miltek, panel filters and rpi scoops.

Fast forward there have been times the car has just felt seriously under powered. got on with it.

Fast forward 4 months on, just routine, changed to brand new eventuri panel filters, brand new maf sensors for good measure. took everything apart and fitted it myself. a few days later idle problem started. basically at the lights or stationary the idle would be very lumpy and feel like missing. The problem remained intermittent here and there.

So i took everything apart, air boxes etc and put back together checking all parts for any leaks etc.

now i have engine management light on. idling has gone worst when stationary. but car drives fine and the power seems very good.

had it plugged in a mates garage, reading was dmo/dde bank mixture running too lean?

So far this is what the car is doing:
idling funny only when stationairy
when warm problem seems to go away
a good speed run does cure the problem
sometimes it idles fine, randomly it doesn't, mind of its own

so far ive been told its a leak of some sort, vacum/boost etc. i have checked everything and cant see any visual leak?

The car has not been on any long journey for over a year. maybe it needs a good run? car has 30k miles.

genuinely cant understand, all suggestions and questions welcome

[AWF10M5]

Change all plugs and coils

New Maf and o2 sensors

I? did all that in my car and idle much better not to mention gas mileage has improved. My old o2 and plugs/coils were shot. I? have catless dp and front grill intakes.

Still sometimes car idle a little odd when it's cold here and there but I? think that's just the motor.

[harry007]

new plugs and new maf sensors already in

[Goranot]

If it’s issue with 02 sensors will it bring up error code?

[Anthony3DHeli]

I got two F30s with N20B20 engine (i know is way different to the S63TU) and they do the same when they stay longer than 24h in garage without starting the engine. it's last just a feel seconds then its fine. Its looks to be normal!
I own a shop and tested the Oil, fuel, electronics modules and spark plug, all fine!