I bought a 94' Mustang V6 from my cousin. Did not pass emissions and it wasn't running real good, so I ran the codes. I replaced the MAF sensor, didn't help. Finally replace the O2's and codes are fine. Runs like crap especially when you first start off it misses, and coughs. I have changed, gas filter, plugs, oil, serviced tranny, did back pressure check for bad converters, and cleaned throttle body, and most emission items. I've be told it was anything from a sticky valve, to the coil pack. Still runs a little rich. I've been working on it for so long, I can't think straight. I know I've missed something simple. Anyone have any ideas?