Car is a gt and I stalled on me one day, it.

Car is a gt and I stalled on me one day, it started right back no problem. The next day when I started it the guages did a full sweep whuch was unusual so I started checking everything and the negative battery cable was loose. This fixed the sweeping guage. But the car is now sometimes hard to start. It will crank and take about 15 seconds to catch and slowly build the rpms up. It does not always do this. If you turn the key on and let it set for about 5 seconds it will crank up normally. It idles at about 500 in gear and 650 to 700 in park. I have replace the crank sensor, tps sensor, cleaned the iac, cleaned the mass air sensor, replaced fuel filter. The mass air and iac each test to be good performing test with the volt meter. I have also checked the fuel pressure and it seems to be in spec. It goes up to 40 when key is on, is at 30 when idling and when you unhook the regulator it goes up to 40 and all this is what the book sayes it should.