I have 93,000 miles on the original engine. When starting the vehicle when cold I am getting engine misfire codes on cylinders 2,4 & 6. The smell of raw gas is very strong and there is a noticeable loss of power. When the engine gets hot it seems to run fine and sets no trouble codes. The plugs have been changed about 30,000 miles ago and the plenum was changed about 10,000 miles ago. I am not missing any coolant unless it is just a drip or so. Any ideas?