I have an 09 LNF with 41,xxx miles on it. During the colder months, the motor would sometimes admit a loud clicking sound for only 1 or 1.5 seconds right after the motor fires, post-starter, and then it would quickly go away. Has anybody had issues with this? It only happens once in a while.

Also, sometimes during cold start-ups, the motor would make a funny sound after 2-3 seconds of firing, accompanied by a temporary drop in rpm. It would last maybe a second, as it is a temporary plummet of RPMs and some sort of clunk sound in the motor. Has anybody experienced this?

Both problems occur while the motor is cold, not after it already warmed up.

 

The first one is direct injection, and there's a sticky right at the top of this here sub-forum about it.
EDIT: It's a different sub-forum, but here ya go... https://www.cobaltss.net/forums/08-1...icking-124678/

The second one may be also. It's hard for me to follow exactly what's happening there.

 

Mine makes a "rattling" sound for about 1 second on cold starts occasionally if that's what you mean.