Morning of issue Ranger was idleing, making a tapping sound, in evening with​ a fridge in bed, went over a bump being cautious since fridge, the Ranger popped up in air just enough for the engine to start knocking really loud and loose RPM. When I accelerated the knocking became less. 1200000 miles and oiltoil change about a month ago. I'm not an auto savvy at all but I can record sounds. So please any direction, advise, expectations, thoughts, should I rebuild or just cut losses? All and any help is much appreciated.

 

Well, I ain't no mechanic or audiophile, but that almost sounds like you have a big gaping hole in the headers. Strange you chose to put this in the Audio & Video tech section, might explain why nobody responded?