Rough running engine at temp

Hello, I have a 2000 nissan xterra that has been running great! The other day while driving with everything running normal and no warning the engine started to run really rough and the check engine light came on (first time at 140k!). I pulled in to a parking lot and took the truck out of gear and let it idle. It would idle fine for a few seconds and then bog down over and over. I let it run for a few minutes like that to observe the symptoms and then cut the engine. After waiting a few minutes I tried to start the engine, it would turn over and try to start but would not start. I walked to the local burger stand to ask if there was a mechanic or auto parts store near by and there was so I walked there. I talked with them for a few minutes and they said that they could run a code check but I would have to get the vehicle over to them. The engine had a little while to cool (approx 45 min) and started with no problem so I proceeded to drive the 3/4 mile to the store and just as I pulled into the parking lot the engine started running rough again. Codes were P0340 and P0325. Same thing the following days, it would run for about 5 miles (guessing till operating temp?) and then start running rough. Hope this is not too much/little info....