Forenza not starting
 

My daughter's 2004 Suzuki Forenza was misfiring and overheating, so the mechanic replaced the plugs, wires, then the pulleys, timing belt, water pump. This took care of the misfire and overheating, but now her car won't start sometimes. Acts like it wants to start, then spits and sputters and dies again. I was wondering if it could be the fuel filter, or fuel pump or just bad gas. We did add the dry gas additive to her tank yesterday.

Also, if it's possibly the filter, do you have to replace the pump too?