I have the same issue right now.
The plugs, wires and cap were replaced recently. So IF its the head gasket would there be any exterior leaks?
Also, I have noticed when driving around 50-60 mph the rpms want to jump from 1600 up to 2000. It's NOT going in and out of OD, just revving. It will do this 2-3 times in a row then goes a little ways then does it again.
Are these issues related?
How expensive is this or is it time to put on Craigslist?