2000 4Runner won't go over 3000 RPM

I am having problems with my 2000 V6 auto "stuttering" @ 3000rpm. It seems to be dumping raw fuel into the exhaust. It is running very hot before the converter, converter is not plugged, MAF is changed, O2 sensors changed. It is burning the mufflers up ( 3 in 4 months ).I see alot of issues like these in different forums, but no resolution,Please Help.

Thanks,

Brian