neighbor lady husband recently died and has 2006 pacifica 3.5-husband always took to sears-this time I think they got her-has p2097-down stream fuel system 1/2 rich-they put 2 o2 sensors on-not sure if oem or aftermarket.light still comes back on w/same code-alldata says possible causes-ex leak(none),o2 sensor(??),o2 signal/return circuit(switches),fuel contamination(quick trip gas,took sample,looks ok).here is what I have noticed-hooked up actron scan tool and monitoring long/short term fuel trims,st toggles 0 plus/minus 5.0=long term usually 0.0-eng will start to miss very badly almost like running on 3 cyl-stft goes minus 28.5 or higher and long term goes minus 32.4-then as it almost dies,iac /computer/strategy picks up or quits missing and will run fine for about 45-60 seconds then misses again-never dies-code is probably result of cause of miss-what I have done-checked fuel pressure(good)checked spark plugs(has ngk factory ones)plugs are not gas fouled or black-replaced all 6 plugs w/ngks-looked at valves w/bore scope for condition(ok)checked for coolant leak at w/pump area(no crusty orange)wiggled wiring when eng misses to see if concern goes away(did not) road tested for approx 10 miles (never had problem)let idle about 5 minutes and it started missing again-unit is in closed loop-do not know where to go-she is distraught-car has 68k-any help appreciated-I am ford tech and dont know late mopars-HELP-thanks in advance rick