It sporadically, but quite often, cuts out when I'm driving?

Hello, I have a 1995 Caprice Classic. It sporadically, but quite often, cuts out when I'm driving and I have to play with the gas pedal to get to to drive smooth again. I have to be very careful pulling out into traffic in case it bogs down. This has been going on for about 2 months. In that time, I have had 2 diagnostic checks done. I have replaced the distributor cap and rotor, spark plugs and plug wires, the ERG valve hose, battery, exhaust manifold gasket, thermostat, upper radiator hose and fuel filter. I have also had the entire exhaust system flushed and checked by Midas. I replaced the water pump 2 summers ago. I still have the problem and the mechanics are stuck! Any ideas on what else it could be? One diagnostic was done before repairs and another after all repairs. The above repairs have cost me about $1400 (the dist cap and rotor was $600 because it was so hard to get to). The car has 132,000 miles on it. Hope you can help me, I'm running out of money! I would be glad to donate if you can help! Thanks.