Mine does the same thing. Checked with my friend, a long time Japanese engine mechanic and he told me to use thin oil to allow to raise with more ease and use Meta Lube, but I have not seen this item in the stores. He says it's not the valves, but the lifters which have a very narrow opening and becomes a little loose with time and use. He says it's no big deal unless I want to do a head job, I should just let it be until it really needs fixing.

1985 Toyota 4x4 4Runner. 1989 Suzuki Sidekick 4x4.