I ran a buddy of mine in a cobra last night, I pulled him at least 3 cars. After 6 runs or so my car would break up in high rpm's. I get home check underhood, and noticed spark hitting my header. I pulled plug out to find it shattered from the middle. What could cause that? Also i'm running ngk iridiums, but i do not have that o2 sensor connected as im waiting for the extension to come in. could that play a roll?Please help guys

 

Overtightening the plug or tightening it at a wierd angle could do it.

 

I would bet that there is something wrong with the actual plug. Not the car. However, it is kind of stupid to be driving around with no O2's. My car ran like **** and I only drove it about 2 miles home like that. However, under full throttle, I believe the computer by passes the O2's readings? I read that somewhere? So under full throttle, if you have a bad O2 it wont miss ... I think the plug was defective/too tight?