1985 4Runner Running Roughly

[MotorsportTech]

My EFI 4Runner sounds like a loping V8 at idle, and it's misfiring at speed. I changed my plugs, wires, cap and rotor, fuel pump, coil, and just tried a different MAF, and still nothing.
Could it be failing alternator? My battery is old and weak and I'm going to replace it tonight. Any suggestions? Thanks!