Can I Get Good Liposuction Results on Mid-section Years After a Tummy Tuck?

Your question is very common.
You should have a reasonable result from liposuction at this point. The only uncertainty that I can see could result from the unlikely possibility of your having greatly stretched the tummy skin with the weight gain.
In such an event, you possibly may have some skin sagging after liposuction. This is mostly seen with a large weight gain. Be aware that even if the skin was slightly looser, it will not be visible in clothes. So, the result may well be worth it.
I would direct this question to your plastic surgeon and see what he/she feels about this likelihood.
I hope this was helpful.

In principal, the answer to your question is yes. However I would consult your prior surgeon, especially if you were satisfied with his/her results for a definitive answer. My general approach to patients seeking body contouring is to offer liposuction, first because thinning out the subcutaneous layer may be adequate to meet their needs. However I have had patients, like yourself, who have returned after tummy tucks, requesting some "fine tuning" and have had successfull liposuction, which did not leave excess or baggy skin. Good luck.