Okay. So a few years ago, i bought a used 1991 mustang 2.3 L that was in rough shape. After a while tinkering on it and trying to get it fixed up to be my daily driver (mainly because driving around a mini-van as a daily driver is not very....manly). So I fixed some wiring issues with the ignition system and the fuel pump, got and installed brand new coil-packs, plugs, and plug wires, starter and solenoid, belts and even the timing belt. And now after all that its backfiring like nobody's buisness, possibly missing (though its a little hard to tell through all the backfiring), and just in general running rough. The strange thing is, it seems to run fine when its in park/neutral, but when i switch it into Drive or Reverse or what-not, it starts running poorly. Any help is appreciated. Thanks in advance!