My Mi16 (XU9j4) seems to be running lean. When it had an MOT a couple of months ago the tester said it appeared to be very lean when he tested it. It also feels a bit flat when driving, though seems to idle OK.
I know many things can cause this from fuel pump, AFM, sensors, etc. But any tips on what I should focus on checking first? I don't have any kit for testing fuel pressure, but can probably test most of the electrical things OK.