A common problem we came across with that engine in and around that year was with the Mass Air Flow System. The Mass Air Flow sensor is located on the intake air tube to the throttle body. You will be able to tell the component by its location in the 3" intake air tube and the connector that is attached to the sensor. On the sensor is a flat area close to the connector. Have an assistant start the vehicle and raise the RPMs just above idle until the engine smooths out. (Take care to keep your hands and clothing away from any moving engine components.) Tap on the sensor on or near the flat area (like you are knocking on the door of a house)and note if the vehicle stumbles or stalls. If this occurs replace the sensor. If this component does not fail the tap test it would be in your best interest to take the vehicle to a repair facility that utilizes ASE Certified Technicians to do a complete diagnosis of the concern. Because of the many components that are on this engine that could cause the concern you could replace a lot of parts and still not have resolved your concern. I hope this helps. Happy Motoring!!!