4.6is stuttering

[04e53x5]

Hello guys. I brought my 4.6 to have a water pump replaced air recharged and determine why the ses is on. Little over a month there I just picked it up. Every thing seemed fine air cold driving smooth no lights on. Stopped for gas filled it up. On the way home it started to stutter and was shaking at idle. The ses flashed twice and went off the whole ride home stuttered a bit no ses for the remainder of the drive home.
While it was there the right cylinders had a bit of carbon build up and that was causing to throw a code. They tried sea foam not to start to take the engine apart Code went away no ses then passed inspection.
So for the strange and random ruff idle could it be from it sitting for over a month with out it being really driven as well as some seafoam still not burnt off? Possible a tank of bad gas?

Thanks guys!