4.0 V6 pinging?

Anybody else hear pinging or knocking with their V6? I should start out saying I really don't know if it's pinging since I've never actually heard what pinging sounds like. I've heard it described as marbles in the engine when the engine is working hard.

This sound started about 3-4 months ago and I noticed it mostly when commuting on surface streets. It only happens when going about 30-50 mph when the transmission has up shifted so the RPMs are fairly low and the engine is almost lugging. It does not happen, or at least I can't hear it, when I take off fast.

I've run 87 octane ever since new and never heard it. I switched to premium a couple months ago and it seems like the sound has gotten better in the past 1 month.

When I took it into the dealer a few weeks ago I did a ride along with the mechanic and he said these engines are known for pinging, but he could not replicate the sound.

finally i have met someone with the same issue as myself. i have an 07 quad cab tacoma that is doing EXACTLY the same thing. not sure how many miles you have, but mine started around 17k and has done it since until just recently (at 38k). i have complained about it numerous times, first few being told it could not be replicated. i went on a road test with a tech when i knew for fact it was happening, he heard it, and could replicate it when i was there. 2 weeks later, i get it back with the write up being for a cv joint and the description stating my complaint, an acknowledgement by the tech, a toyota tac case being open, and "after comparison with a similar vehicle on the lot, the noise has been deemed normal and by design". complete bs if you ask me.

for me, the noise was most pronounced after a solid warm up period on warmer days. i have been thrashing on it out of frustration figuring it was something that was about to let go. i read about the pinging, and despite not believing this to be the cause, switched to the next grade (89 octane), the noise is all but gone. i am now getting horrible smells from the truck after a good acceleration. not sure if you are also experiencing this. it also has a very "brassy" sound to it just before coming to a stop that i have narrowed down to the drivers side exhaust, right before the cat. it sounds like a whining steering pump for a lack of better description, but it is from the downpipe.

anyhow, i'll keep you posted. it is going in for the pedal replacement and i am going to have a different dealership look in to the smell, sound, and an explanation as to why the truck can't run on 87 as it is advertised and recommended for. i refuse to believe that this is by design since you are now only the second person i know of who is experiencing the exact same issue as me.