I didn't say "smell the exhaust" but if there is black smoke pouring out at idle and it is idling rough then id say yes there's a problem..
It should run fine with a lex afm and 550's. It should also run fine with lex afm, 550's and a walbro pump as long as your fuel pressure is adjusted to oem spec.
Walbro 255 is a higher flowing pump than the stock unit. It is also running at a constant 12 volts. The stock pump at idle is running on 9 volts. So, wouldn't you think you would be getting more pressure at the rail with a higher flowing pump running @12v, with the stock FPR(that was designed for the stock fuel pump and 9v at idle) and j-pipe still intact? Im not sure the stock ecu can correct afr's enough IF he's running super high fuel pressure.
First try and take the j-pipe off the engine and drill it out. See if that helps at all. You really need a AFPR and gauge though. An SAFC wouldn't hurt either so you could do a little tuning. Just make sure you have the wideband in place before you start messing with the SAFC.