"94 Olds won't start

I have a 94 olds 98 that will not start.It will crank over just fine but it won't fire. I seem to have plenty of fuel and spark.It started as a stalling problem,the car would stall usually after driving several miles. Every time it stalled I would get a message that read "HOT...AC Dissabled". It would usually start back up,but it would run terrible.I have changed the coils,plugs and wires temp. sensor and PCM. I scanned it just two days ago,and got two codes: 342 cam. sensor (replaced with new one,still wont start) and 670 Qdm failure. I'm not sure what Qdm is,but I think it is something in the PCM.Has anyone else seen the "HOT...AC Dissabled" message? Also the HOT will light up by the temp. guage (digital dash) but the guage reads normal.This happens even when the engine is ice cold.PLEASE HELP!