I've been having this problem for a couple of months now. My car has a rough idle and from time to time the rpms will drop to almost zero. When I'm driving and I press the clutch when slowing down the car will stall sometimes. When it first started doing this I got a cel code p0134. I replaced the primary sensor and it went away but I still have the same problems. I decided to replace other items hopefully it would go away. I replaced map sensor, primary O2 sensor, spark plugs, serpentine belt, new cai filter, cleaned IACV. I've done the system idle relearn everytime I replaced a part. Now I have cel code p0172 which tells me system is too rich bank 1. I haven't replace the secondary O2 sensor. Do you guys think this could be the culprit or should I look into other things also? Starting to get desperate and irritated at the same time. Don't wanna take it to a shop.