I have a 1999 Mazda 626 that has a cylinder 1 misfire. I have changed plugs, wires, coil, injector, and oxygen sensors using only OEM parts. Still, this car is misfiring on the #1 cylinder! All cylinders are at 180 pounds on compression tests, and the plug IS firing. What am I missing?
If you car is a 4cyl I would have a good look at the ignition coil that is on the side of the cyl head (this also applies to the v6) and look for any disdoloring inside the wire holes and look for cracks or arcing on the body of the coil. Also it would be a good idea to make sure the intake manifold gskt (4 cyl) is not leaking.