I am infrequently getting CEL warnings regarding fuel ratio errors on my wife's 850 Turbo wgn. Car is running fine, just have the annoyance of the light coming on and worrying my wife :-) I have had to reset a couple occurences of both P0170 long term fuel trim and P0171 - system too lean. When I watch the real time fuel trim reading while at idle, WOT, and part load it looks to be normal but my long term is way out there at about 22-25%. Over the past year I have replaced both O2 sensors, looked at all of the usual vacuum leak suspects, and used a stethoscope to listen for vacuum leaks while engine was running. All of the normal "tune-up" items were done within the past 18 months -- new plugs, wires, cap and rotor, air filter, fuel filter. Anybody that has any helpful tips, let me know. Thanks