could these mods be screwing up something?
 

I have a 1990 rx-7 with a 13b in it. I can take the car down the road and it will run very well If I don't get on the throttle hard. But if I get on it hard in first then shift to second and ride out second the check engine light will come on usually before I have to shift to third or no later than like 30 seconds after i shift to third. When the light comes on the car sort of wants to fall on its face until I come off the throttle. when the light is on i can drive the car easy [not matting it] and it will not effect driveability. But if a I lay in to the throttle the car holds back and doesn't want to respond. But If I ease in on the throttle it will run fine at high rpms and everything. The car is in really good condition besides this problem. The person before me did the following mods: A/C delete, rats nest removal, racing beat header and full exhaust, relocated the battery to behind the passenger seat, and has a cold air intake that is only like 12 inches away from the maf sensor. Could any of these mods cause these problems?

Pull the codes to find out why the ECU is faulting.