My 1995 Tacoma with a 3.4 v6 has been running very rough and has no power. I have replaced plugs, plug wires, O2 sensors, MAF sensor, and changed the fuel. I get a misfire code on cylinders 2,4,6. I pulled off the plenum and the intakes to cylinders 2,4,and 6 are clean. The intakes to 1,3, and 5 are very dirty. What would cause one bank to differ so much from the other?

SOURCE: maf?/ missfiring

have the map sensor checked to see if it is within range you say you have codes maf make sure all clamped duct work is tight and not loose clamps .iac motor clean bore if the pintle gets stuck will cause rough idle hesitation even no start conditions scan tools only test the idle air control valve motor not the bore that extends to block varnish gets built up on the pintle and in the bore wich binds the in and out operation

SOURCE: 5vz-fe misfire codes

Replace the coil pack.

SOURCE: the 4runner is throwing 3

Replace the coil pack..

SOURCE: 99 4runner 5vz-fe 3.4 misfire

I know this post is old, but right on the engine theres a sticker that says use multi-ground plugs only. I read a similar problem like yours and it seemed to turn out that the spark was arcing to ground over the ceramic on the plug. So maybe it could have something to do with the single ground plugs.

SOURCE: Tacoma 4cyl idles rough, heditates, multiple misfires

Possible fuel delivery problem, fuel pump, fuel line, clogged fuel filter, leaking injectors or injector O-rings, faulty pressure regulator etc. Check your fuel pressure.