02 Xterra 4WD low mpg after tune up

I have a 02 Xterra 4WD Manual transmission. I recently replaced the plugs, wires and distributor. Since replacing those parts I am actually getting much worse mileage and if you stand too close behind the car while its in neutral, it will make your eyes water its running so rich. Its also very sluggish on acceleration and has basically no power.. im wondering if I have the ignition timing off from when I replaced the distributor, but this is my first time owning a Nissan vehicle, so im not too familiar with the commonly flawed parts.

Thanks in advance!