what would cause Back fire?
 

Tonight i was driving home the car was sluggish (very sluggish) like it was adding to much fuel or something but i was driving home i step on the gas and i hear POP and i swear they flames must have been 4 feet long from the dual tips. It was insanly bright..... No one saw it tho....

What would cause this? the car has been acting sluggish today..... it all started when i was changing the coolant and got the engine wet...

.

tps probobly got wet

O2 sensor bad...

Lots of things it could be;

Incorrect Ignition Timing
Malfunctioning Electronic Spark Advance System
Leaking Intake System
Incorrect Idle speed
Defective TPS or Fuel Pressure Sensor
Defective ACV or AAV
Malfuctioning BAC
Leaking Injectors
Faulty AFM / Intake Temp Comtroll
Defective EGR

Start Checking one by one. Run your engine codes too, it might tell you something. Just a thought :)

i would check all your electricals since water might have touched loose wires.

bump

Why bump? The answer was posted.

The car is running rich. Various reasons as stated above. If you don't have any emissions equipment, it is fairly normal for the car to backfire.