I recently had my oil changed. Dealer forgot it took 5w-30, instead they gave me 5w-20. First time running 5w-20. Prior to the oil change, I was having a stall issue. Not from acceleration, but from deceleration and would happen often. Ever since the 5w-20 went in, it hasn't stalled once. No rough idle. Nothing. Runs smooth! Any opinions as to why the 5w-20 would clear that up? Dealer is replacing my next oil change for free. Just curious to know what people think.