[jcb986]

I had one come up when I changed the plugs...didn't get the connection on tight. During a test drive, I got a little miss after a few miles and the check engine light came on. I knew the one that I was having a hard time getting snapped back into place and it did pop lose. Once I had it back on correctly the check engine light went off after several drives. The computer will automatically reset the cell after so many cycles...I believe it's 10. So your problem could have been a misfire or anything, but the problem went away and the cell was reset. Check and see if the code is still stored, this will point in the right direction.