"could" in the present and past tenses

[Mazen]

Dear teacher,
I'd like to know the difference between the following sentences:

I could do what I like.

and

I could do what I liked

best regards
Mazen

[Tdol]

The first is present or future time and the second is past.

[henry]

Dear teacher,
I'd like to know the difference between the following sentences:

I could do what I like.

and

I could do what I liked

best regards
Mazen

In addition, the first "could" is less certain than " can ".
e.g. I can do what I like.( certain)
I could do what I like.( less certain)

[Mazen]

Thank you very much
:)