torranosaurus

Hello,
I took my 2006 xB with 318,000 miles in for an oil change. When I fired it up to leave the quick lube, it started running bad, and the check engine light started blinking along with the trac lights coming on and staying on. I pulled over and got an error code of P0301.
Went back to the shop and we looked it over and did not see anything obvious. I reset the light and drove home, about 5 miles. At first the thing ran rough, especially on acceleration. The dash lights did not stay on though, they came on and off.
When I got home it was sputtering a little, but no engine lights at all. I put it in the garage and revved it and it seemed fine.
Any ideas?
I commute over 200 miles a day and need to feel better about getting in it tomorrow morning. I do have an Echo parts car that is not driveable, but the engine runs. Maybe I can swap out parts to see what is up?

Again, any help would be appreciated.

_____

torranosaurus

Update:
Cylinder 1 spark plug was all rusted up. Replaced all while at it and it is running great.

torranosaurus

Well folks.
It happened again today. I pulled the coil and the top of the spark plug is sitting in a little bit of water. That would explain why the first plug did what it did.
I am afraid I might have the head gasket leaking into the top of the plug. Anyone know if this is possible, or would it leak into the cylinder? How else would the plug tunnel have water in it?
Help!!!