I need advice on what might cause this.

The car runs fine until I floor the accelerator, and then its out for a couple of days (until I reset the ECU, and leave the key in for like half a hour). Could this be a bad ignition transistor unit? Idle Air Control? Already replaced the fuel pump itself. This is an 2+2 Auto NA (non-turbo)

Bought the car not too long ago and never noticed it till I floored it and got stranded.

Any advice will help, its kind of not possible to drive it around if I can't floor it every now and then.