2003 Chevrolet Trailblazer running rough

The truck started running rough and then the check engine light came on. I put it on a computer and the only code was a ph300 I think. So I put a new coil on number one along with all new spark plugs. It ran like a new motor. Later on that same day it started running rough again, and a new code said it was the cam sensor and map sensor. I put the cam sensor but it still ran rough. I hooked the computer back on and the code said I needed a cam sensor again the only code this time. I also cleared the computer six or more time by unhooking the positive battery cable. In short, the truck will run great for awhile and then it starts running rough with the RPM running up and down. I put it in neutral to keep it running. Last night I was on the freeway for half hour, it ran great until I pulled in the driveway and it started running rough but no light came on. This morning went to work it started up and ran great. What do you think it might be?