I read in this forum about testing for a rod nock by removing the plugs one by one till the knocking stops. Should I do this while the engine is running or do I stop the motor in between each plug I pull? And I am pulling the plug wire not the entire spark plug, correct?

I have a '93 F-150 5.8L 150,000mi that has started knocking. On my last oil change, I took the truck to a dealership to get a little insight as to what they thought the knocking was coming from. They said it sounded like it may be low end and at the mileage I have replacing the motor was my only option.

I was told before that the knocking was lifter related, and didn't really pose a problem, but after my last oil change (10W 30) the knocking was more evident, till I added a pint of STP oil treatment. Now knocking is noticed on RPMs below 2000.

Thanks for any advice, my intent is to take it to a reliable mechanic, but I don't want to get reamed in the end.


Gary

 

Yes, pull the spark plug wires one at a time while it is running.