Mal58 replied:

Mark,
Most V6 Petrol Engine Prados have an engine resonance at approx 2800 rpm. In some Prado's it is more pronounced than others. It is quite normal.
Unless it is extreme, then there is nothing to worry about. It may be worthwhile comparing yours to some friends Prado's just to ease your mind.
I found that mine was "quieter" when I used premium grade petrol, but the finances don't permit that very often, plus, I don't believe I received any benefit in either performance or economy when I did.

Rgds,
Mal58

Paul replied:

Mark - Different situation but I was concerned about a similar vibration in my diesel Troopy at 1800-2000rpm and was told the same 'resonance' thing. 206,000km later it's still there and hasn't caused a problem.

Werner replied:

Hi Mark, I have a 1994 2.8L diesel 4runner and vibration seems to occur at around the 2500 rpm mark. It disappears once you go either above or below that point. I haven't worried about it too much.

Norm replied:

I also have a V6 Prado which does the same as far as the vibration is concerned. Mine now has 67,000km's on the odometer and it does not seem to have affected it in any detrimental way. I also have a friend with the same vehicle same vibration.

Cashy replied:

Mark,

I believe this is a known problem with some of the earlier V6 Prado's with some vidrations as you describe. Toyota id produce a kit to fix it. But I am lead to believe that it required you convincing the service department that it was a problem and it was covered under warranty.
Hope this helps.
Cashy

Anthony replied:

I have a 97 RV6, and have experienced some minor vibration at 2,800rpm also. I have covered 115,000 k's without problems, however the fuel economy has gone west, from an average 14-15 lt/100k to 20.
How is your economy, any suggested fixes?