My suggestions are primarily intended for DIYers, and you need to be aware that most shops are likely to be reluctant about requests by owners, especially when those things do not appear in the documentation they subscribe to. Now in this particular case, testing the VCM should be a reasonable thing for them to do, because the VCM is easy to remove and test by applying voltage directly from the battery. And if the VCM doesn't test ok, then replacing it is easy as well, although they will likely want to get the part from a Kia dealer for around $400 or so. (versus ordering online for less $$)
However, if the VCM tests ok, then removing/reinstalling the intake manifold is a time consuming job, and would be billed at 2 hours or more, which translates into $300+. And they are also likely to be very skeptical about possibly resolving the issue by cleaning the manifold, based on advice from a forum.
So consider these things before speaking to them, in order to plan what your response will be, depending on what they have to say.