I also have a slight hesitation sometimes, well it sitting at a light or just idling. Not every time more info if I hit the brake I hear what sounds like a pump. Low tone.( Moan) my car has 45 k and no check engine light. It did start and shut off once but never again last week. I use car as a dally driver. Not issues while driving just at idle. Please respond if you had similar issue. Or know what this could possibly be. The dealership is 4 hours away. The car is 2006 flying spur.

 

The engine has a normal hiss at idle (towards the rear of the engine). It is usually not a vacuum leak. The moan noise you are hearing is the secondary vacuum pump. They get really noisy as they age and eventually self destruct and require replacement. Since the engine is turbo charged the vacuum pump is required to maintain stable vacuum for emissions items, exhaust flaps in the tailpipes and brake booster. If the vacuum pump runs constantly then you either have a vacuum leak or a bad pump. It normally runs after pumping the brakes, especially at cold start

 

You are so on point! It is exactly as u stated. I still get a small stumble at idle sometimes, only when it's warm. And not every time. Maybe just time for plugs. No lights or misfires though.

 

The occasional stumble is not uncommon. At 40k, you are due for the major service (plugs and filters). Sometimes the stumble is caused by a faulty exhaust gas temp sensor. It will set a fault, but often times will not trigger the light. There is also a recall on the ignition coils. Get them done if you haven't already and avoid having your engine washed or "Detailed" It will save you a bunch of trouble down the road. The coil recall is done free at the dealer

 

Coils have been Done @18,000 miles.. Will have svc done soon with plugs.. Need Brakes too ouch.. so trying space work out..

 

hmm interesting