Here are codes thrown after it had been cleared pictured below and dash lights where EML 4x4 and brakes maybe 1 moreIf you want to look for a vacuum leak.. Get some brake cleaner and while the engine is idling roughly.. Spray brake cleaner around hose joints.. At the intake manifold.. Around the throttle body etc etc... If you have a vacuum leak the engine will suck in the brake cleaner and the idle will fluctuate... This way you can narrow down a possible vacuum leak to a certain area..
When you replaced the alternator did you tighten all of the intake hose joints and Maf sensor connections..and or any connections you loosened.. Double check... It could be something g very simple..
Also is the check engine light on... I would think you have trouble codes pending in the computer.. If there are codes.. They will go a long way in helping you isolate the problem..
Sent from my S8 Active