FLMarine

I have a 2005, 2500, 4x4, quad cab with 257k miles, stock injectors, oil bypass system, and rebuilt the transmission at 170k with an upgraded single disk converter. I've owned it since new and it's been kept in very good shape mechanically with only a very light tune on the Smarty Jr. Two days ago it was surging at idle from 700 ish rpm to about 800-900 and had a rough idle. With the high idle enabled it idles fine with no surging at all. Ordered a new FCA and replaced it, which helped but it still has a rough idle and now is surging from about 700 rpm up to about 750-800 rpm somewhat in a regular pattern. Occasionally I do get a little bit of white smoke on cold start ups, but that's done that since it had about 50k miles on it.


I do have a P0483 code, but I just had the fan clutch and compressor replaced about 18 months ago and I noticed a frayed wire on the plug connector so I think that is a different issue.

Any suggestions on what it is or experience with a similar issue? Thanks