im lost. started the car to burp my cooling system. had the front raised on jack stands and letting the car run well about 15 minutes into coolant starts shooting out of my radiator. not just over flowing flying out alot so i shut the car off fill system up with water and close the radiator cap. start the car up and and its idling eratically jumping around so i give it a little gas and the throttle response sucks then the car backfires. what can be causing all of this where should i start? what would cause the coolant to come outta the radiator the way it did? all help appreciated.