1997 Buick Century Cranks but no start

As I cranked the vehicle over, it will not turn over at all. Obviously it has gas in it. But before this all happened.I hooked up a scan tool to it and it showed that I had both a egr flow insufficient and a cylinder 4 misfire code. However, as I crank it up and give it gas, it will run as long as I keep my foot lightly on the gas. Once I let it up off the gas, it will die. I was thinking of that misfire code and a possible clogged fuel filter. I bought a fuel filter, but I still need to put it on. Also, I don't know if this had something to do with it, but my car got hit one night on the drivers side fender as I was sleep. I was told that it could either be a bad throttle position sensor, bad iac valve, or a bad map sensor.