96 GST missfire, not building boost please helo lol

Hello all, so I bought this 96 GST yesterday and barely made it home, it has an intermiting misfire that mostly stays, but if the car is under neutral condition (middle of accel/decel) it smothens out, but once you apply more throttle, then the misfire comes back and also I can hear popping noises coming from the intake. The guy I got it from said that his dad had installed a new head on it and that something was off with the timing, but the wires seem to me OK, so I don't know whats going on, I just want it to run right, can anyone offer some assistance? 96 GST 4G63T 5SPD. Thank you.

Well if a new head was installed I would first check that the timing is right on the timing belt. If your getting back fires into the intake than than its possible that it could be wrong. Second I would check for any vac leaks and boost leaks. They will also cause the car to run like shit.