Replace the ground cable under the drivers side rocker panel that attaches to the engine block. Also clean up the ground point the cable attaches to on the frame/subframe.

I had the same issue and nothing changed after swapping out the alternator (which had a bearing on the way out anyway, so luckily it wasn't for nothing).

I've thought about adding additional ground cables as well given that the main cable I mentioned above is much more prone to corrosion, etc. given it's location. Considered adding a cable from one of the top alternator mounting bolts to the block, but haven't had a reason to mess with it just yet.