Hi Brian
The check engine light is on but has been for the past 15 years, regarding the codes I'm not sure about what the mechanic found but he said it wasn't anything out of the ordinary. I just went out for some short drives the past few days & the truck ran smoothly this time with a slight miss. The only difference is the outside temperature which is close to 50 F. This is mind boggling to me trying to sort out why it runs terrible for over a month & now it is running smother again although they were only a short trips.