cylinder 4 middle back is wedged by the o2 sensor, if the socket cocks on the plug, it snaps it.

ive done it before myself on cars with headers that were a tight fit, good old cyl #8 with a/c on a big block chevy= 3 universals and extensions lol and a snapped plug every now and then.

since then i always use spark plug sockets. the rubber inside keeps the plug tight to the socket, and it cant fall out of the socket either.


if you dropped a plug, that could have cracked it too, but then you would have also needed to drop one from the other set of plugs as well maybe?

spark plug socket.