Okay, I will try and describe the problem that I am having to the best of my ability. I have a 2000 Crown Vic P71. A while back the engine started missing. The "idiot light" came on and I had the guy at the zone run the code tester on it. It came up "cylider 4 misfire" so I replaced all 8 of the plugs and coils. The damn thing was still missing so I thought maybe it wasn't getting enough fuel so I replaced the fuel filter (i did the air filter and pcv valve that day too) and it was still missing. I thought maybe a clogged injector. I ran injection cleaner through the fuel several different times. . . nothing. I have put seafoam through it, nothing. I have checked for vacuum leaks and found none. The "idiot light" came on again yesterday so I went down to the zone again and this time it was "cylider 7 misfire". The engine sounds just fine, but when I drive it (especially during slow accelerations) it is clearly missing. I used to get about 300 miles to a full tank, now I am lucky to get 230. I am really stumped on this one and I am not sure what else to check. It may be something easy that I have been overlooking. Does anybody have any suggestions?