did you change the weight of oil you use? that is the sound of the chains slapping against the tensioner pads until the oil pressure builds up. all oils have a cold weight and a hot weight, and there's been some discussion about the weight of oil to use to ensure that all the oil doesn't run off the chain/pads if the car has been sitting for a while. the slapping will slowly deteriorate your tensioner pads and you should see the green plastic start to show up in your oil filter and, presumably, a representative change in deviation.
I had that problem and it went away when I did two things (three, if you count having all the problematic pieces of tensioner pad get abraded away ...):
- changed to 5w40, and
- updated the oil pump piston.
the oil pump piston is #26 in this parts diagram:
Oil Pump
(note that you should also change the spring #25 and the washer #5). the piston is there to ensure adequate oil pressure on start-up. in our cars it has a square edge and apparently it can bind. for the 9x7 they beveled the edge to solve the problem and updated the part # for the 9x6. the change is easy; 5 mins with your next oil change, and the parts cost all of $10.