Knocking when I put load on, also accelerating from a stop

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If it quacks like a duck, it might be a stuck valve or a push rod, just like you thought. Also, ensure you're using the correct fuel grade, as lower grades can cause knocking. Worn engine mounts can also lead to noises under load. But I think pulling the valve covers will tell you all you need to know or hopefully eliminate the valve train as a culprit. Good luck! If you have any other questions, please call us at 877-913-1554! We'll gladly find you a certified RepairPal shop in your area!