96a4z28

ok , this weird stuff started happening with my car a few days ago..first the car sat for a day without me driving it ..then the next morning when i cranked it up and started to drive it it sputtered alittle and didnt feel normal..it usually drives real smooth..my first impression was that i had bad gas in it and it caused the car to do this ..then the same morning not long after that the service engine light came on then i really knew somethin was up...well since the car was kind of low on gas i went and put like 5 gallons in. then slowly as time went by , the light went off ,and the sputtering stoped..dont know if it was cause i put the new gas in or not. it was fine for the rest of the day .then just today..i cranked the car up and the same thing!!..only this time the light came on 4 mins after driving and it was flashing!!..(service engine soon light)..and it hasnt stoped yet...has this weird situation happened to anyone else yet?..now just right now when i got out the car i noticed some antifreeze leaking down when i parked it!(geez great)..what could it be..could it be something clogged like a cat?..all i have done to the car is the muffler removed thats it..i got the car only 2 months ago and havent had any engine problems whatsoever until now..sorry for this being so long..any help would be appreciated..i might have to get this scanned for codes...thanks alot guys
96 a4 z