I have been having a constant problem with my 1990 Ranger 4.0 liter. About every six months it begins to run rough and is lacking power and eating threw gas. I have replaced the coil pack, plug wires and plugs. This took care of the problem for about six months then it started running rough again. Any suggestions? I was told it could be a bad Mass airflow sensor but i dont wanna go throwing more parts at it and have the same problem again down the road. I love my truck and would love for this problem to be solved. Any help or a solution to this problem would be greatly appreciated

 

Also i forgot to add that the exhaust smells horrible you can tell the truck is not running right

 

check your cat sounds to me like shes starting to get cloged up.