My check engine light came on so I went and had it read. The error code said that the 4th cylinder wasnt firing. So i replaced the coil, the spark plugs, and the spark plug wires. The light can on again. The only time I notice a difference in the car is at an idle. The RPM go down to 700 and the car feels like it going to die. Its a 96 GS. Any ideas? Im giving up!