11 535xi rpm spikes before going down when breaking

[Ch1tah]

I just changed engine filter and cleaned maf aensor
as car was throwinf p112f code. Code is all clear
but i notice when breaking speed goes down but rpm spikes a little
Before going down, is that normal
also i have some rough idle

[MarcoZandrini]

The first step in diagnosing a problem is to scan the engine conputer (DME) for codes. The Service Engine Soon light is on only when an emissions related code is present. Rough idling could be vacuum leaks. With the engine idling at operating temperature disconnect the MAF. If it idles smoothly, the likely cause of the rough idling is vacuum leaks.

[ross1]

Does sound a vacuum leak, perhaps associated with the plumbing to the brake booster.

[dworthy]

+1

Easy way to test is to turn the car off and pump the brakes. Count how many times it takes before the pedal goes still, a good booster is about 2-3 pumps, a bad booster is maybe 1 or none.