Ford escape loud noise

I have a Ford Escape 2006 when you start the car it makes
a really loud noise it sounds like it's coming from the
engine I have replaced the alternator the exhaust pipe the
serpentine belt catalytic converter oil change the
transmission oil was okay but when driving the car it
struggles to pick up speed the RPM gauge once in awhile
jumps and if you push the car too hard it will stall I have
taken it too many mechanics and still don't know why it's so
loud I need my escape to be quiet is there any idea out
there as to what could be wrong with my vehicle can
anyone help me out please give me some ideas I would
greatly appreciate it cuz every mechanic has a different
answer as to what is wrong one mechanic said take apart
the engine another said check the belts and another
mechanic said it's the timing chain so I would really greatly
appreciate a more decisive answer please and thank you
for the help