Hi, i have noticed on my 3.0 V6 diesel, that low revs on light load are pulsating. First i thought that maybe the gearcis too low, and because of small load, the gearbox does not shift.
Aleays hear the pulsating rumble in the back of the car as the exhaust pipe would be vibrating on pulses to some bracket.
But noticed, that when i accelerate slightly, having fixed gas pedal possition, the revs from 1000 to 2000 build up in pulsating way.
The higher the revs, the weaker pulsating is.
Can it be the fuel pump problem? Lack of pressure?

 

When the trasmission oil have been changed?
Torgue converter slip lock and some other friction plates on transmission work with oil pressure -> Old oils don´t maintain pressure and can cause slipping. -> Slipping cause wear/high temp for the friction plates -> Oil loses its charachters faster. This is a spiral of death.
By ZF (manufacturer of the transmission) one sign of old oils is rpm humping.

 

Haven't thought about gearbox slipping. Because that would mean that fluctuation would be like revs jumping up / torque down. Now i have revs falling down / torque also down for that moment.
I mean when you have stable revs, on gearbox slip the revs fluctuate up. In my case, revs fluctuate down. Added video. But the audio did not catch the muffling sound.
As i have now info about service history before purchasing it, have no idea if it was changed at all, and i haven't done it yet, since drove about 10k km.
Also about the fluctuation of revs, have noticed in one forum (for Honda Ridgeline) very similar issue, but it was due VCM programming and it was supposed to work like this initially. But don't think x351 has this.
fluctuating RPMs / bouncing tach; any ideas? | Honda Ridgeline Owners Club Forums

 

Unless you have lot of slipping and time to time grapping. Then you have rpm dropping.
Check when your gearbox olis have been changed. Its easy DIY job and ZF deliver very good instructions with their kit and even video on their youtube channel. (the gearbox:ses are NOT sealed for life, expect if you like that the vehicle lifetime is 150t km)

 

Check for MAF codes. I have had surging like that at low revs on cars with dirty/failing MAFs.