Hello, I have a 2015 Subaru Forester 2.0xt premium with 115 thousand miles. I have a problem starting it when its a cold start, it seems to chug and almost choke for the first 10 seconds or so. Then after a minute or 2, when the engine is warmed up, it runs quiet and smooth. While driving, it does does stall or shake when idling. When it's a warm start up after driving, it does not sound as loud or chug as much as it does on a cold start. I recently changed the spark plugs about 1 thousand miles ago. Thank you for your time!
Well actually that's a classic sign of a vacuum like somewhere in your intake system. Vacuum leaks will make cars run poorly when they're cold and when they come to an idle when you go in faster, the engine sucks so much air that a small vacuum lake doesn't affect the running. Then. I would start by looking for a vacuum leak
