Lately, SES comes on and then goes off itself. But past couple of days stays on.
Basic scanner reads: P1092 pre-cat fuel trim system too lean bank 2. (All O2's changed almost 100K ago-Cats orig). But when I read the fuel trims I got a negative. New plugs about 10K miles ago: 4 prong.
1.8 - 3.%. I have many other readings when capturing live data, just don't know how to read them.

1. X starts up perfectly every-time, first time, no lag.
2. MPG's right on schedule, current tank running almost 260 miles half tank.93oct.
3. Acceleration is wonky. Sometimes super sensitive and snappy, other times a little lagging. Tank volume has no influence. Obviously, snappy coming up to running temp. Then not consistent from time to time.
4. NO major oil consumption. But a minor pan leak. Some coolant loss, not sure where or why. Minor suction at idle with oil cap removed. Not intense.
5. It's a really old X, 255K miles. 01. 3.0.
6. Vibration when braking in DRIVE or Reverse at idle, but none at neutral.
Fuel filter/reg is at least 10 years old n 100K miles. Vibration an engine idle issue?
7. Engine, tranny mounts changed 50K miles ago.
Trying not to just throw parts at it. What's a good place to start?
I am going to do basics: Clean air intake system, TB. Check for vacuum leaks.

Thanks.
J

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X5 3.0 AUTO -2001 - 238,000 miles