Rough Running 1996

My Son Aquired This Car From A Neighbor Who Gave It To Him Because The Shop Said It Needed A New Head Gasket And He Didn't Want To Put The Money Into It(body Is Rough And Has 90,00 On It, But Hey It Would Make A Great Cheap Car To Run Around In). The Head Gasket Was Replaced (head Was Also Checked..it Was Ok). When They Started It Up It Was Running Rough And Surging. It Already Had New Wires And O2 Sensor. Check Engine Light Comes On , Exhaust Smells Terrible.
It's A 2.2 Automatic.
Neighbor Said Check Engine And Temp Lights Would Come On But It Never Needed Water, So It Wasn't Really Overheating.that's Why He Had It Checked Out.
Any Help Would Be Great
Thanks!