1.1 mm
specification on gapping spark plugs for 2006 chevy cobalt
.035
18436572
Listed under the hood on a placard and in your owner's manual.
Ummmm......... I think you want to use spark plug wires.
depending on what engine you have, 4.3 v-6 or 305 v-8 or if your lucky the 350......chevy never ran a crank sensor on an engine that old. If it wont start, check spark, if you have spark, check fuel.
To add, this is a 5.7 v8 engine.
45 ths.
V8
on the left side of the motor by the spark plugs
bad fuse,bad coils, bad ignition modual