I drove my car to town last weekend with no issues, shut the car off and it set for about 3 hours. I got back in to leave and it wouldn't do anything!! No power to nothing, I figured loose battery cable or battery dead so I checked cables and hooked booster cables with no luck. Had a friend try to push me off since its 5 speed and it fired but wouldn't run. I let it set for about 20 minutes and it fired up like nothing was wrong. On the way home I started to down shift and the engine revved wide open. I am thinking bad ECM any advice would be greatly appreciated.

 

Possibly a bad or loose ground wire?

 

Would a ground wire cause the engine to rev wide open though?