My 2002 (first half of year style) Dodge diesel 3/4 ton with 170,000 miles on it does this gentle subtle yet noticeable bucking especially when still cold. I had cleaned the injectors with fuel treatment and did not like the results. So I did it by pouring the howse directly into the fuel filter after draining current fuel out of it and idling for about 30 seconds or more and shutting it off and letting it sit. It seemed to help. But a few months later now it is doing it again.

So, not being a mechanic, I have questions.
Could it be bad injectors? Do I find a garage that works on diesels to replace them or can I figure it out and do it if I have half a mind? !! What would it cost? What could be the issue if it may not be bad injectors?
fuel filter replaced 6,000 miles ago.
injector pump, fuel line and lift pump replaced 40,000 miles ago.

Thanks for some input.