I'm new on here and I'm hoping someone may be able to help me. My Smax is sounding like it has a slight misfire, when revved in neutral. It is a 56 plate with 95k miles on the clock. No error codes showing and driving is ok. I also noticed that when the engine is revved whilst moving (with foot on the clutch or in neutral), the revs take a long time to die down when the gas pedal is released; the reaction of the engine to the pedal is noticeably delayed. When revs are applied whilst stationary the response is normal. Any ideas? Thanks.