2000 courgar stalls when put it in drive but fine in reverse

my girlfriend bought a 2000 cougar 2.5 motor and it ran fine going down the road, but, when stopped at a stop light you touch the gas it stalled. the previous owner said it needed a tunup. We changed the  plugs,wires, air filter,fuel filter, oil and oil filter and I changed the idle positioning sensor as it coded TPS when the check engine light came on. The check engine light is off now and none codes. She drove it for 140 miles total the next day and now when you put it in drive it stalls, but not in reverse, you can drive in reverse all day and won t stall. The previous owner had said he changed the fuel pump and coil pak and module as it also has junkyard writing on the side of the module. For some reason his so called mechanic ran a ground wire from the fender to the battery ground and to the block. it has 36-40 lbs. of fuel preasure running and the same with the engine not running. The car has 134,000 miles on it and this thing driving me nuts trying to figure it out and 4 garages latter and no codes showing up and no one has never seen this before - anyone with any idea as my girlfriend is very upset after buying a car and not being able to drive it and her friend will not answer the phone or the door-  so please help me- lol