[TaurusKing]

521: power steering pressure switch issue,, code says no indication of change during koer code test,, when running koer test, you must turn wheel at least 1\2 within a few seconds of engine id code being sent, senses pressure change at power steering unit, pcm looks for this to increase engine rpm when needed, I'm not sure if this is available on all models, some may exhibit this code, but not have the actual switch, in that case disregard it
528: make sure your a\c is turned off, during koeo test, if on, could generate codes 67\528,, happened to me one time with my 87 Taurus, left the a\c switch in a\c mode, got the 67 2 digit,, yours will be a three digit code such as 528, or it could be trans related depending on model, clutch pedal position or park\neutral position sensors
536: has to do with the BOO circuit, brake on\off, pcm looks for this, either it wasn't applied during koer test, or something in the circuit has failed, could be bad ground, bad stoplamp switch, etc.. doesn't really sound like any of the above are connected to your problem of cutting out unless it's in a big roundabout way?? BOO circuit??
I'd start with checking fuel pressure, filter changed recently???, pull dist. cap, clean rotor and cap, they're probably corroded up, check all your vacuum, electrical connections, many miles on this car?? any black smoke when this happens?? Sort of shortened up the code defs, took them off my disc,, koeo= key on engine off,, btw, koer= key on engine running, just in case.