I have a 2000 ford expedition with a misfire on cylinder #4 I have replaces all the plugs and wires and replaced all the coils yet it is still missing. I thought it might be coolant from a hose getting in it but I did a pressure test and it passed it. And I had my mechanic check all the hoses and none of them have a leak so if you have any idea what is wrong please help!

 

Right about now would be a good time to do a compression test. If that passes we can go back and look for something possibly electrical or intake manifold or gasket problem. If the compression for that cyl is low suspicions can be confirmed with a leakdown test. If you decide to do the checks , let us know if there might be anything else we could suggest.