I know vibration issues have been beaten to death but I'm hoping someone might know what the following is or if it's normal:

At idle (park or neutral), motor makes a cyclic vibration about every 4 seconds and it shakes the vehicle. Not severely, but very noticeable.

It doesn't do it when put in gear and the rpms drop to 500 but as soon as it's put back into park or neutral it starts again.

I have the 03 V6. Does anyone elses do this or is something wrong?

 

Could be a possible transmission problem. Torque converter maybe. If you put it in drive and drive the same rpm as it idles, does it vibrate then?

 

Problem is, I've also been chasing a wheel vibration issue since I've had this 4runner and I'm trying to isolate the sources.

Wheels are as balanced as they're gonna get but there's still vibration when driving but I can't tell if what's causing the vibration at idle is the source of the one when driving. It's just not severe enough to be obvious, but it's enough to want it fixed.

I guess I'll have to buy another set of wheels (hub-centric) to see. Dealers aren't motivated, say it's normal.