Nice weather...so went over my bmw 525i 94 touring auto

Last week at the mot place, the guy gave me a can of carb cleaner so today i
took off the plastic to get to the butterfly. he said open the butterfly,
spray the stuff around and clean off with a toothbrush...

I did that, got out lots of black gunk...started it seem fine

I just had to nip to the docs, it cut out a few times at the lights, so i
put it in N with a few revs to keep it going(v long light seq) i put it back
into D then it said trasm problem and was stuck in third i guess..( i was
moving a bit).i got to the docs, with it stalling a couple times, say from D
into R to park, and again when i came out....5 minutes later.

This time no trans problem popped up on display and this time i had kickdown
etc etc no problem, pulls all the way through the rev band

no this is my first auto, so i panic what to do when it stalls...

i did try while going down the hill (steep) i put it in N (as i wanted to
rev it a lot, to clear blast out any crap left in) but it stalled, so i had
no power steering or brakes, so i put it into D at low speed...is that ok? i
know your not suposed to (or it lets you) go into R
or P

I leave for Germany in 48 hours, i got home ok, left it running a few
minutes and all seemed fine in N or P just running...maybe its when i
braking or coming to a stop, so it should be at tick over (or in N and i rev
it, when it comes back down it feels like it wants to stall, then comes back
up to normal tick over)

now im worried...any thoughts v much app!!
ta