2005 Jeep Wrangler intermittent concern

First, intermittent problems can be very diffucult if not leaving any codes, could use more detail...but Vehicles manufactured after 1996 use the ODBII scan tool or code reader, if this problem has turned on the check engine light then the on board PCU has stored this code in memory even if the light has went back out, the scanner can tell you what codes are stored.... you can purchase a scanner right here from this site, but that would be the best place to start. if you want to leave more details on the problem, I will be glad to help if I can