i have a 1991 ford ranger with the 2.3l with 8 spark plugs recently iv been hearing a knocking noise when the truck is going up hill at a low rpm or when the truck is pulling a my jet ski. any ideas on what it could be?
He is talking about the rod and main bearings inside the engine. Now as you only hear this under load i can say that it is NOT the rod/mains going out. Run some seafoam through your brake booster vacume line and see if that helps.