1999 dodge durango slt

:runaround:hello i just purchase a 1999 dodge durango 4/wheel drive 5.2 engine .it has not been started in a year.got it started and change all the fluids.the oil gage on the dash goes up and down resting on half way mark some times.the engine check comes on and goes off .what that all about? thanks have a happy new years to you and your family .cowboyway