afni.nimh.nih.gov

So turns out all I had to do was check the header of the other nii that AFNI is recognizing correctly and make the correction.

I just had to make the same change suggested in earlier post:
nifti_tool -mod_hdr -mod_field dim '4 64 64 1 262 1 1 1' -prefix CO2_ASL_2d_mod.nii -infiles CO2_ASL_2d_whole.nii

Thanks!