94 Camry LE 3.0 stalls and OBD scanner won't link

Initially my CEL was on and when scanned the code indicated a TPS fault.  
Due to my inability to replace the sensor at that time I would just clear out
the code.  Eventually coming home the car died out when turning a corner.  
I could start the car and it would run when idling but if put in gear it would
stall out as soon as I tried to accelerate.  However I could rev the motor in
park.

I tried scanning it with my OBD scanner but repeatedly got a "Link Error."  
Assuming the TPS had caught up to me I ordered a new sensor.  
Therefore the car sat idle for a couple days. When the part arrived the car
was acting and running like a champ.  I could accelerate, no rough idle, no
staling, Absolutely NOTHING was wrong.  I connected my scanner and no
codes were stored or found.  I changed the TPS and drove the car
regularly for 3-4 days before it did the exact same thing again.  I had it
immediately towed to a repair shop who spent a day trying to trouble shoot
but couldn't determine the problem nor would their scanner connect.  I had
it towed again to a friend who is a mechanic.  The car sat for a day or two
before being checked and once again it's working just fine and no codes
are stored and no CEL.

Does this sound like a Mass Air Flow sensor or ECU/computer issue?  The
original MAF was replaced a little over 2 years ago with one from a salvage
yard.   The intake hose to the MAF was also replaced about 6-7 months
ago.  Help.......