ok something really weird happened today. I had to go downtown like 40min drive. some of the drive was slow in the highway in the city. stop and go. usually the needle of the coolant is 1 line below the middle. not sure if this is relevant. it bounced to 1 line above the middle mark then came back down. ok little over heating due to the stop and go. so I arrived at the location and I parked. that's when this happened. I needed move up the vehicle and I turned it on, it started to crank like I lost total power of a dead battery. I hit the gas and keeped it on. it fired up after a while doing this and rpm like hit 4000 even after I released the peddle. so let it sit for a bit running. thinking I let it charge battery possibly. so I turned it off and re tried and it basically back to normal fired up. not exactly sure what may of caused this. will check voltages tomorrow and battery connections too.

 

I would start with checking the battery as you stated. Keep us posted.