Platinums are gapped at 0.60, and iridiums are typically gapped at 0.40... you shouldn't try to change the preset gaps.
With the 2.2 L engine and ACDelco R42LTS spark plugs, the gap is .040".With the 4.3 L engine and ACDelco R44LTS6 spark plugs, the gap is .060".
Click the link.
Spark plug gap chevy ls blazer
.60
.60
the gap is 0.060 inches
You need a 5/8" spark plug socket.
Follow the spark plug wires, they will lead you right to them.
Replace the spark plug wires, too much resistence in the old ones.
06.0 on a 4cylinder 2wd s10
40
Need to know what engine it has to answer that one.
The diagram.