Knocking noise coming from motor

Get the engine oil pressure check ASAP, ensure there is sufficient engine oil, if this noise in more of a rattle under heavy acceleration get the timing check, as this can be engine ping due to an ignition timing problem.

If the ignition timing is out you can get engine ping, that sounds like a rattle under heavy acceleration, get this checked first. Also bad fuel can cause this as well, that is if the problem is ping or pre ignition which is another term for it.