I have a 1988 Jeep Comanche 4 cyl. 2.5. I have a slight miss, a compression check 150 lbs, on 3cyls, and #3 cyl. has 120. When i pull the plug wire off each plug, it will miss, but when i pull it off #3 it it don"t change. Also there is spark from the plug. Is it possible the carb. its running rich, it seems, from the smell. Can low compression actually be the cause. thanks