When accelerating from a stop, my 5 speed 3.9L with 3.55 rear gears pings sometimes on regular. Using premium, i don't hear that noise. Motor has 280,000 miles on it. I wonder if this vehicle was equipped with a factory knock sensor? Thank you.

 

As you can find out from the factory service manual (copy downloadable from a link in the FAQ ... no excuses for not having one!) no, no, it doesn't.

Try a mid grade.

Or, what I would do, is to give it the Seafoam treatment and see if you can decarbon the heads and pistons a bit.

If you DO overhaul it, consider EngineQuest heads; they have a much better quench design and resist knocking. Along with breathing better.

RwP

 

Thank you for answering my question and I will take your sage advice into consideration.