After my last major 4.1 tune-up there has been a slight hesitation when pulling out of my driveway. There is also some periodic hesitation when coming from a stop light, but usually it's all gone by the time the engine warms up. There is no hesitation when sitting in Park in the driveway--it only happens when I put it under load, and mostly only when the engine is cold.
This started happening after the last tune-up, which was pretty substantial and included things like GM top-end cleaner, new plugs and wires, and lots of other stuff. I'm pulling together parts for things that were missed like EGR valve, O2 sensor, breather element, and I'm planning on having the injectors tested and getting a leakdown test, so hopefully I'll get it with all that, but I'm curious what people think. My suspicion is that either (1) the condition existed before the tune-up but the engine running weak hid the problem before, or (2) deposits got knocked loose and are clogging something up. Any thoughts?