call autozone or other parts store and they will give you this advice free
spark plug gap on vauxhall astra 1600cc 2002
.040
.024
Plug gap is 0.7---0.8mm,or .028"---.032"(28 to 32 thou)
One at a time
.040
.028"
No...
1-4-3-2
Between 0.025 and 0.028 is recommended.
1-3-4-2
From .044 to .028 depending on: year, motor size, ignition system, fuel system, plug type.