93 300e will turn over but want start

[jointheir]

i have a 93 300e and just recently i changed the wires and plugs with no problem with the car starting. About a month ago the car was driving rough vibrating real bad.Took it to the shop mechanic said a plug might of filed out because it was not running on all the cylinders. I changed the plug, than the car went back to normal. I drove the car out of town it drove fine until i came back, it started to vibrate again. I decided to change all the plugs and wants i done that the car would not fire. The plugs are getting wet but no fire. The car is turning over but not starting

Pleas HELP Me