1997 Chevy Camaro Hesitation

I recently brought my car in for repairs to a trusted mechanic that my family has been using for years, due to a hesitation and need for a wheel alignment (due to purchase of new tires). The car began hesitating about two months back, and I have since learned that my check engine light was on but is burnt out. The car hesitates and jerks randomly while driving, it has happened on the highway and also during inner city driving. The car occasionally stalls and dies while driving, and also while idling. The mechanics initial beliefs based on the fault codes, was that the computer itself was in need of replacement. The computer was replaced, but still showed crankshaft engagement errors. So the crankshaft sensor was replaced. The car's ignition module was then replaced and was returned to me. Upon getting the car I tried to start it up, and it wouldn't start. I called the mechanic and left a message as it was out of hours. The next day the mechanic said the car started right up. I came back to pick up the car, and it stalled and backfired right infront of the mechanic. He then kept the car for a few days trying to diagnose the problem and replaced the spark plugs and wires. But hesitation, stalling and starting problems persisted. The engine coils were replaced, based on the fact that he believed the coils were short circuiting the module. I got the car back, drove for a few hours down to a friends house, and the car stalled yet again while driving, and not shifting, and began to back fire, and hesitate, and when the gas was pressed the car wouldnt move. The repairs was about $1450 and the car is worse off, do you have any ideas of what it could be? My friend said it may be an 02 sensor, or possible too high idle speed, and/or a plug in the catalytic converter. Thank you for any help