Yeah, mine's a weird problem. The noise stops and starts depending on throttle position (and even that varies). I can be maintaining say 2000 rpm in 2nd and it will make this noise, if I back off the throttle completely it may stop, or if I slightly increase throttle it may stop. Then it may stop and start at various times again depending on how I'm driving. After a few minutes (and it seems to be lasting longer over time) it will stop completely. I'm assuming this is because something has warmed up sufficiently.
I would have thought lifters would have been a constant ticking who's frequency would vary with revs, but be continual until it got warm.
It doesn't seem to cause any performance problems, it just sounds like crap and is embarrasing.
Don't mean to take over this thread, but I think we may be having similar issues.