I posted this problem a couple months ago...no one really knew what it was and appartenly niether do a few mechanics...

when i start the car after it's been sitting 8+ hours, it makes a chugging noise until the engine is warmed up...it sounds like a bad valve tap, but only for a few minutes until it gets warmed up. The drive belts were replaces 8 months ago...i brought it to a couple mecahnics (one is usually real good) but they said they didn't notice it or it's normal, but it never made this noise before and i don't know why it would start now...

one more note...it's a 97 max and i'm coming up on the 120k service...i switch to sythetic oil at 100k

 

That noise is coming from the passenger side of the engine near the cylinder banks? Sounds like the timing chain to me. Try a heavier oil and see if it disappears.

 

yea...it's coming from the passenger side...seems like it may be coming from somewhere by the drive belt...i use 5-30 now...you think 10-30 would help or maybe the timing chain is getting worn?