Please state engine type...3.1 or 3.8?
Of course head gasket problems are 3.1 problem, not 3.8....
What part of Gatineau is this? hull, aylmer, gatineau?...this is on George street,or very close, is'nt it?
COmpression test seems a little weird..but sometimes it is hard to have a tight fit of the gauge, so maybe the 80 on #1 is accurate....maybe not...but this , anyway, is not necessarily linked to the trouble you describe.
Not sure if your .94 codes can be flashed...but anyway try this when you have the CEL on..
www.avigex.ca/xport/readingcodes.jpg