Bought a 2014 2 door Rubicon 6 speed last November with around 52000 miles. Ran great up until the start of warm weather this spring. Got light with p0300 and p0306 codes. Replaced spark plugs and cleared codes per Jeep dealer. Light stayed off for about 3 weeks. Replaced coils, camshaft sensors, and crankshaft position sensor. Didn't help. Changed all 4 O2 sensors. Didn't help. Been driving it with the light on for 2 months. Ran great with a little roughness at idle. Last week it lost power light was flashing. Pulled over and it died and wouldn't start. Same codes. Dealer said bad cylinder head. $3500. User's recommendation: Don't buy a Jeep with 3.6.