2002 Dodge Dakota, 3.9. 90% of the time it runs perfect. However, sometimes when at a stop light, it will stumble and miss and quit running. It restarts and runs good. Have replaced both up stream 02 sensors as well as the Idle Control Valve, spark plugs and wires and distributor cap, the MAP and TPS, and 3 fuel injectors. Also, replaced the fuel pump. No code comes up. Any ideas?