2007 Dodge Durango That Starts Occasionally Recently Would Start Sometimes

I HAVE A 2007 DURANGO THAT STARTS OCCASIONALLY. IT RECENTLY WOULD NOT START.SOMETIMES AFTER SITTING FOR A FEW MIN. IT STARTS.IT RECENTLY LEFT MY WIFE STRANDED. IT WOULDNT START.WE LEFT IT OVER NIGHT THINKING IT WOULD START.IT DIDNT.CALLED A WRECKER HAD IT TOWED TO A MECHANIC.UPON DROPPING IT OFF THE MECHANIC SAYS IT CRANKED ON THE FIRST TRY. I TRIED TAKING NEG. POST OFF AND REPLACEING IT.SOMETIMES THIS WORKS.BUT NOT THIS TIME.HAS BEEN A ONGOING PROBLEM FOR A FEW MONTHS NOW.ALSO RPMS GOING TO 3 SOMETIMES.AND NOT IDLEING DOWN I HAVE TO STOP AND RESTART THE VEHICLE AND SOMETIMES IT IDLES DOWN.HAD TROTLLE BODY CLEANED.IT HELPED FOR A WHILE THEN STARTED ACTING UP AGAIN.PLEASE HELP.AT OVER A 100 DOLLARS A TOW GETTING PRETTY EXPENSIVE. THANKS STRANDED BUT NOT?