I recently pulled the heads of and had them redone.

While they were off I replaced both sets of timing chain guides and two of the tensioners.

After I put it back together I began having an odd issue.
When the "D" is cold or after sitting for a while, I start it up and all is fine.
No noises, strong oil psi runs good.

After several minutes the oil psi begins to drop and a while longer it is low enough that it makes the noise like it is low on oil.

Still it runs fine.

But I am worried.
What could have happened or what I could have done wrong.

More important what can I do to fix this?

 

If it makes the noise that it is low on oil, it probably is low on oil. Don't drive it. Look at a faulty sending unit perhaps.