Hi,

Maybe someone here has had a similar problem and can shed some insight here.

I've got a 4runner Limited V6 3.4L, with 218,000 mi. I started noticing a knocking sound about a week ago that seems to be coming form the passenger side of the engine and seems to be in the middle or lower portion of the engine. The knock is noticeable at operating temp at idle and less noticeable at higher rpm and when under way. (This may partially be due to increased road noise.) The knock is not noticeable when engine is cold. The knock seems a little louder when at operating temp and in neutral or when the engine is NOT under load. If I put it into drive and step on the gas and the break at the same time to create a load the knock is less loud but still there. I've had the 4runner since 125,000 mi. and always run it with mobile1 change oil 2 times a year.

Thanks,
Chris

I had this problem awhile back, found out it was my knock sensor that was bad, and the wiring harness was pretty much melted. Got it replaced and no problems ever since.