Suggestions please:
 

I had a hell of a week. Long story short the 3.8 L's are prone to burning oil. I blew a motor just under 60 K miles and had a short block rebuilt at the end of 2011. Currently I have 78K miles, Since then I have had to replace my spark plugs 4 times as cylinder 3 keeps cracking my plugs. Every shop/dealer I've taken it to has no idea what is going on. I just wanted to post something to see if anyone else has had the same problem? Right now I'm replacing the coil pack, new plugs, new wiring and hoping for the best this is now the 2nd time I'm doing this in the past 8 months. Any suggestions? My warranty expired on the short block as it was 12 months 12,000 thanks.

...it could be a timing issue or excessive heat...The jeep may be running lean or could be something simple as incorrect spark pug gap....