In all the years using 8G plugs in those engines I only had one fail.Not much you can do but use a brass punch and hope for the best in getting the chambers out.
1996 GMC Sierra ext.cab Z71....with new genuine GM 6.2 660 short block,4L80E/6.5TD cylinder heads,DS4 5521S,82' 6.2 rocker arms,acdelco TP1069/Racor 20S fuel filters,4" diamond eye exhaust,3.73 G80 locker,stanadyne 37818 injectors
1996 Chevy K1500 Z71.....with '99 6.5 506 goodwrench van engine,88-93 6.2 diesel Napa y-pipe,'87 700R4,acdelco TP630F/Racor 20S fuel filters,Bosch non-turbo injectors,stanadyne blue tag 5088
1993 Chevy K1500 Z71...with 97' 6.5 TD 506 block,82' 6.2 rocker arms,Bosch injectors,stanadyne blue tag 4911,DSG girdle,reman 700R4,Banks boost/pyrometer gauges,acdelco TP1069/TP943 fuel filter system,4” diamond eye exhaust/2 piece crossover
2008 Mercedes Benz E320 3.0 V6 turbo diesel
2013 Volkswagen Passat 2.0 TDI