Sound coming from exhaust

[bignasty27]

Hello everyone,

2009 4.8i with 133km's

For the most part, truck has been reliable with all the predictable quirks found this forum fixed. The truck still has many original parts and hasn't needed major service at all aside from control arms, brakes, oil changes etc.
Replaced CVV last year due to rapid oil consumption due to recommendation found on this forum and it seemed to help. Had to add 1.5 quarts after 4000km which was a vast improvement over the 1000kms I was getting previously. I know that I will eventually need the valve seals done but aside from the oil consumption, which isnt too bad right now, I am not getting the smoke at idle out of the tail pipe or blue smoke or anything like that but I know it will eventually need to get done.
Recently, I have noticed a lowering of RPMS at idle and a little shaking (vibration) when I come to a complete stop. Listening outside the truck, the right exhaust sounds strange to me almost like a "PUTT PUTT PUTT". The left side doesn't sound at all like that. I have attached a video hoping that someone has an idea of what it could be. Could it be a symptom of the failing valve seals?
I am due for my 8000 km oil change in about 6 weeks and will get my INDY to check it out but hoping to get everyone's thoughts before hand.

Thanks!

[bignasty27]

Just an Update:

Got a CEL and is it was Misfire Cyclinder 4. Because I already had access to the ignition coils, I changed all 8 coils. Runs better , smoother but "PUTT PUTT sound from exhaust is still there and so is slight vibration at idle. I reposted the video on youtube hoping for some replies.

BMW Indy mechanic thinks it may be related to valve stems and seals but I am not sure how that is possible.

Have also unplugged MAF with engine running and sounds disappears. I plug it in again and "PUTT PUTT" doesn't return until I restart the engine. Perhaps someone can explain why that may be, perhaps computer doesn't reset values until engine is restarted?

Could a bad DISA valve resonant through the exhaust and make that sound or just in the engine bay?

Any help would be great!

https://youtu.be/9FHzVU0g8l4