I have few problems with my VW Touran 2005 1.6 MPI, LPG with manual transmission:
On average one in a few startups on cold engine, ends up with exhaust pipe noises like gunshot when I press gas pedal, and engine is choking for about 10 seconds after startup when I slowly drive
Very rarely with warm engine when I stop and set the gear to neutral, RPMs does not drop to idle and even slowly go up, and after pressing gas pedal a bit they quickly drop to idle (of course after I stop pressing gas pedal)
Yellow sludge appeared under oil cap, but that may not be a problem because lately I was driving short distances in cold weather (and as far as I know it can happen in such conditions)
So what problems can cause such behavior.