The generator matrix

 1  1  1  1  2  2  1
 0  2  0  2  4  0  0
 0  0  2  2  2  6  0
 0  0  0  4  0  4  0

generates a code of length 7 over Z8 who´s minimum homogenous weight is 4.

Homogenous weight enumerator: w(x)=1x^0+16x^4+34x^5+16x^6+126x^7+13x^8+30x^9+16x^10+2x^11+2x^12

The gray image is a code over GF(2) with n=28, k=8 and d=8.
This code was found by Heurico 1.16 in 0.000296 seconds.