I have no idea what it is, I can smell unburnt fuel, it wont stay at idle, it wants to die.
I have a video.
It's a 1993 Lexus SC400 without vvti.
It was low on oil but then i put some more in, i had a oil change done like 1,500 miles ago.
Some people said it could be misfire of coils, some say it was rod bearings, and I've dug around something about timing chain.
Before having this problem sometimes it would stall (sometimes) at idle.. I know fuel pumps also like to take a turd but idk.
Google Drive Video

 

Most likely a dead coil on one bank. Try un-plugging each of the coils separately and see if anything changes, if it doesn't, you've found your culprit!

 

Replaced both, still making the same sound. I’m guessing it’s the timing chain.