Thanks to overdrive and all of you guys for the tips given.
Well, I took the car to a porsche dealer to explain them what happened. The guy read the codes and found a long series of misfires on third cylinder and some other knocks.
He told me that misfiring are potentially dangerous for timing chains (and I partially agree) and he wants to investigate better from where those things are coming from.
I didn't reset error codes so I can read them in the future because I don't believe to take the car to him to get it fixed. I have an idea about this issue and some of the codes are getting me convinced. In the next days I will take the coils and spark plugs off and check them 'cause I'm pretty sure is someting related to them. Te engine is running smooth, with no vibrations or whatever strange. But obviously this s m opinion. I will later let all of you know what was wrong with it.
@ghostrider: I experienced a rattle noise just from the engine bay time ago. It was coming from the water pump bearing which was replaced while the car was receiving a new clutch kit and some other expensive (
parts. Maybe you have the same problem if you have never replaced the pump.
About the IMS bearing, I have checked it personally while doing the clutch and it doesn't seem to have any play or leakage or broken bolt. I just did maintenance a couple of weeks ago, after the last one approx 15k km ago, and had a look at the filter element without finding any plastic or metal residues. This made me happy considerig that car have 170k km. Anyway, for the future I count on the Raby's IMSG to monitoring that bearing.
Thanks again guys, I'll let you up to date with this issue. I really appreciate.