I have a 03 Jeep Liberty 3.7 I got a code of 1296 and P0301 what are these codes

Thank you.... the reason I changed the gasket was dry rot. and little oil drips on the driveway. I did unplug some of the sensors to get them out of my way b/c the valve cover was not easy to get too. I took my time and only had to replace the PVC b/c the cheap plastic broke. I'll you up to date on what happens. Thanks again Tom Okay I unplugged all the senors and the hoses.... took my time and plugged them back in I walked thur my steps.... I cleared the code (1296) started the jeep back up it ran for about 2 mins then the code came back on(Check Engine Light) I put the code reader on it and again Code 1296.. I need some real help now. I have no clue Thanks Tom

You still haven't clearly said whether or not the check engine light was on BEFORE the gasket job.