I've noticed my 4.8 has developed a bit of a heartbeat. It's inconsistent, but there's a rhythmic, or slow pulsing vibration coming from the drivetrain. I can feel it in the steering wheel at stop lights, and if I let off the break the car will inch forward in time to the pulse.

Any thoughts? It's weird but I'm seeing no symptoms of other problems.

Interesting.

I have noticed this recently too, '06 4.8is. car got about 150K.

Would like to hear opinions...

Also an '06 4.8, 95k. From what I've read on other forums it could be spark plug related but that feels off to me. It doesn't happen all the time and there's consistent power delivery. MAF maybe? I'm at a loss.

spark plug, eh? well, if that is the case, this is little blood... I am hoping to change the valve stem seals within next couple of months, and plugs along the coils are on the list. as well as the coolant pipe...

Could it be something else?

Mine has this as well. I was going to replace the 4 vanos solenoids and the IVM as a manner of maintenance to see if it improves. If not, I dread that it's the motor mounts... :(

Yeah, I thought about motor mounts too. I'm hoping that's not it though - my (wishful?) thinking is motor mounts shouldn't impact the crawl at idle I'm seeing. It moves forward in time with the pulses in vibration.

Is there a name for this behaviour?

like some other things in bimmers have names - trifeca, shark fin, kidney grill, angel eyes... If there is a name, then it would be easier to search other forums for ideas...

Yeah, I'm still doing the vanos solenoids, ivm, and a maf cleaning before even thinking about tackling the mounts. I'm fairly hopeful though from the other info I've read about those particular items fixing small idle issues and fluctuations. Maybe it's the optimist in me.:dunno:

@Terminator... I don't know if there is a coined vernacular for this particular problem, but I figured (and have used) a google search for n62 idle surge and n62 idle fluctuations as being fairly good.

Suggest more troubleshooting rather than chase with parts. No Codes?

Not a one, other than the recently developed thermostat fault code which will be remedied soon. :dunno:

I'm a preventative maintenance whore anyway so I throw perfectly good parts in the trash all the time. The added peace of mind I have while driving out of state or with the whole family makes it worth it to me to scatter a few known to fail parts at the issue.