Greetings! I'm happy to be a part of this community! Hopefully I can pick some brains on this issue, but mostly this is to see if my suspicions can be confirmed as to the cause. My 2001 Civic LX, stock original 1.7, 207,178 miles, has recently started running rich. I noticed this as my fuel economy has gone from 30mpg average down to 26mpg average. I checked the live data on fuel trim and noticed that it is subtracting between 4% and 8% on short term and around 7% on long term. It idles smooth at around 700 rpms, but when driving last night, when I depress the clutch while braking, the rpms will drop to the point that the car will shudder and come close to stalling. This even happened at the gas station after fueling up when I was letting the car idle for a bit. First time that's happened since I bought the car. The exhaust manifold does have a crack in it, but that's been there since the car was purchased. The upstream O2 sensor has been replaced with an OEM Denso sensor. I suspect it's dirty/clogged fuel injectors that are causing the issue. I've added some cleaner to the gas tank, with three more bottles in the trunk that I'm planning to add at my next fill-ups. Hopefully I can get some confirmation, and if that's not the issue, some next steps to track down what the issue is. Thank you in advance for your advice.