I have a '93 Z28 with a intermitent misfire on cylinders 3 and 5. I had the cap and rotor, wires, plugs replaced when the water pump went out and the problem went away. Shortly after it returned and I took it back to the shop and they replaced the cap and rotor, wires and plugs again and the problem was fixed again. Now its back and I'm beginning to wonder where the problem really is. Any ideas where I could look before I go back to the shop and they replace my cap and rotor, wires, and plugs again?