Hey guys so I recently noticed a certain vibration while idling. I drive a 2008 s60 and it feels like my s60 is struggling to stay on while im idling at a light while in drive. The best way to describe it is the vibration that you feel when you first start your car. I notice this type of rough idle every 5 seconds or so while its in drive. It doesn't make this type of vibration when i have it in park. I started to notice this after one of my pipes on my fmic became disconnected. I was driving and the pipe popped off causing the car to turn off so I got it towed. Every since the pipe was reconnected, this started happening. I also got a CEL that said my oil was too rich. The light went away however and hasnt returned since. As far as my exhaust, i have a 3.5 downpipe with a catless exhaust. I am looking to replace the exhaust with a cat exhaust soon. Does anyone know if theres anything i can do to get rid of this rough idle? I read about replacing the o2 sensors and my s60 has about 105,000 miles on it.