The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  X  X  X  X  X  0  0  0  X  X  X  X  X  X  X  0  X  X  0  X  1
 0  X  0  X (a+1)X (a+1)X  0  X (a+1)X  0  X (a+1)X aX aX aX aX  0  0  X  X  0  X aX aX aX  0  X aX (a+1)X (a+1)X (a+1)X (a+1)X  0  0  X  X  0  X aX aX aX  0  X aX (a+1)X (a+1)X (a+1)X (a+1)X  0  0  X  X  0  X aX aX aX  0  X aX (a+1)X (a+1)X (a+1)X (a+1)X  0  0  X  X  X  X aX  X (a+1)X  X  X  X  0  X aX  0 (a+1)X aX (a+1)X  0 aX (a+1)X  X  0 aX
 0  0  X (a+1)X (a+1)X  X aX aX  0 (a+1)X  X aX  0  X aX (a+1)X  0  X (a+1)X aX aX  X  0  X (a+1)X (a+1)X  0 aX (a+1)X aX  X  0  0  X (a+1)X aX aX  X  0  X (a+1)X (a+1)X  0 aX (a+1)X aX  X  0  0  X (a+1)X aX aX  X  0  X (a+1)X (a+1)X  0 aX (a+1)X aX  X  0  0  X (a+1)X  X (a+1)X aX  0  X  0  X aX (a+1)X  X  0  X aX aX aX  X  X (a+1)X (a+1)X  0 (a+1)X  0

generates a code of length 89 over F4[X,sigma]/(X^2) who´s minimum homogenous weight is 267.

Homogenous weight enumerator: w(x)=1x^0+192x^267+30x^268+15x^272+18x^276

The gray image is a linear code over GF(4) with n=356, k=4 and d=267.
This code was found by Heurico 1.16 in 2.72 seconds.