Originally Posted by Tagdot
OK thanks for the replies, I knew I didn't break the plugs installing them.
I say if in doubt, take them back out.
Before I knew exact plug torque specs, and before I had a torque wrench, I overtightened a plug, somehow cracking the ceramic part, which I am pretty sure gave me a bit of a miss, I cannot remember if it set any misfire codes though, as this was many years back.
Torque info below taken from AllData.
Tighten Spark plugs to 15 Nm (11 lb. ft.) . NOTE : On the 3800 engine, aluminum heat shields are used over the spark plug boots on cylinders which are close to exhaust tubing. Care should he taken to ensure these heat shields are fully seated.