I have 04 sedan with premium package it has 158k miles which still runs strong but today for the first time when I went to turn it on in the morning it made a big clunky shaking noise coming from the engine area but it turned on and little bit of greyish smoke was coming out the exhaust pipe.. but as the engine got warmer noise went away I checked all oils , belts , etc.. all looks good dont have a service egine light on .. after no noise no vibration & checking everything I could I decided to drive around a bit starting off slowly then gradually add speed but didnt floor it like crazy either & still runs good & strong....

Any ideas?

Mine will sometimes have a clunking noise on a cold start-up but it goes away almost instantly and I have always wondered what it was too.

Hey what oil thickness do you use on your car... i.e. 5-30 , 10W-30, etc..?

Check your oil level. At your mileage, the engine may be consuming oil. You may have to begin the process of topping off the oil every 1k miles or so like I do.

The clunk on initial start-up is a well known concern. Mine has done this on/off for almost the entire 10 years I've owned the car. It's harmless.

If I recall, there is an internal pulley that takes a fraction of a second to receive oil through a set of narrow passages. I tried looking through previous threads, but I cannot seem to find the correct phrase that targets the 2-3 threads that discuss the subject.

The gray smoke is probably unrelated and associated with the car burning a little oil. If the smoke is white, then it may just be the condensation which builds up in the exhaust burning off.