After about five to ten minutes of running, the engine shuts off?

1998 Plymouth Horizon 2.2L 4 cylinder mileage: 115,000. I just scanned all the "stall" questions on your site. Several sounded similar. This car runs well. However, after about five to ten minutes of running, the engine just dies. It may be when stopped or slowed in traffic and it may be running full speed down the highway. Sometimes restarts immediately, usually I have to wait couple of minutes and then starts quickly. I have replaced the pick up coil, spark plugs, rotor, PCV valve, air filter, fuel filter, fuel pump relay and tuned it. Any suggestions or tips would be greatly appreciated. Thanks!