I forgot to tell you that the "surging" in my 1990 Dodge Ram 50 only happens after it has reached normal operating tempature. Hope this can narrow the possibilities and help diagnos the problem(s). Thanks for your help.
Welcome to just answer.com. I'm here to help you and your 100% satisfaction is my goal.It still could be caused by a number of things that's why I would really like to add supplemental fuel to the air intake and tell me if the surging calms down.
Experience: 30 years experience, ase certified,shop owner