Stuck Lifters - Need advice

So, one morning I go out to my 2000 4wd, 4.6 L, Jimmy with ~95k miles on it, and start her up in the cold (8 F) Michigan weather and hear that wonderful tap tap tap of stuck lifters. After a little bit of warming up it seems to go away (and it only seems to because it gets quiet, who knows if it really is unsticking itself).

This is an odd problem to develop since I just changed the oil some 350 miles ago and have been changing the oil every 3000-3500 miles since I bought it (at ~83k miles); I usually do the oil change myself, but this time I didn't have a place to do it, so I took it to the local service station/gas station and they did a pretty thorough job of checking it over and finding all the problems I knew about so I thought, hey they seem reputable.

I'm wondering what advice anyone has for how I should proceed; what should I do to try to solve this problem so I don't damage the engine any further? Also, I've been using a partial synthetic in my engine and I'm wondering if they used a conventional oil could that have caused it to gunk up and stick the lifters (or whatever it is that is exactly happening, but it's that lifter tapping noise).

What weight oil was put in it?
If they did not use it try a good AC delco oil filter.
MT

They put 10w30 in it. Not what I generally use (5w) but I have not had problems in the past at these temperatures in other vehicles so I thought nothing of it.

They put 10w30 in it. Not what I generally use (5w) but I have not had problems in the past at these temperatures in other vehicles so I thought nothing of it.

I would go back to the 5W30 and a good AC delco oil filter.
Good Luck
MT

Sounds good, I'll give it a try.