Car wont start

I just recently bought a 1991 Camaro RS with a 305 V8 from a good friend who took wonderful care of it. Well he recently bought a new truck and the camaro sat for 6 month's before I bought it. Witch ran fine before, now The car would only start with starter fluid at first but would not stay idling. It would alway's stall out. I replaced the TPS just recently along with the fuel filter and airflow lines. I thought it was the fuel pump but when you turn the key you can hear it whine then cut off. So I checked the timing and the belt still turns just fine but little defects along the teeth. So then I checked the spark from the ignition and the only time we could get a spark is when it was maybe a centimeter away from the manifold so I replaced the button and distributer cap and it wont even start with starter fluid. When I read the check engine code it shows code number 53 witch with TBI it say's that it's "System Over Voltage", My queston is that he just gave it a tune up befor he let it sit, Insted of using the original type of plug's he used Bosch platinum 2, would that keep it from starting and if not what do you think it may be? Thanks.