2011 Chevrolet Aveo Lt Problems

Having trouble with my 2011 Chevrolet Aveo LT .
Hesitation comes and goes but getting worse , loss of
power , misfiring . Check spark plugs,  was oil in one
of the wells . Cleaned out and changed ORings and
Valve Cover Gasket , Flex pipe has been changed ,
catalytic converter changed. What could be the
problem? Also hearing this noise . It comes and goes.
Mainly when ac is on . Look below in comments and I
will post a video of the noise.