Back in Feb my check engine light came on and my truck was running rough. I drove it until april 24 the engine light went off and the truck was running fine. I thought whatever was in the fuel line worked its way through. On april 26 my battery ran down from having the door opened for hours. I got a jump and when I took off I wasn't getting any power so now the 4x4 Low Range light is on and won't go off. The truck is running sluggish in drive and reverse. Also the switch was already in the 4L position and I wasn't aware of it. PLEASE HELP!