I have a 1990 Accord with the F22A1 and I was originally led to think it had a bad head gasket but today I pulled the head and found that the gasket is just fine, the head is fine, and so is the block. What gives?

The simptoms were:
~ sporatic overheating
~rough rough idle
~misfiring on steady rpms

I never noticed any white smoke except for a minute after startup. Any ideas? Warped head? Warped block? The car only has 154k miles... I dont get it.