the head gasket is still good if the numbers range in at most 28 psi diffrence so ex... 220 210 220 230 ur ok and u can always rent a compression check from autozone or pepboys or kragen

 

ya hes right mine did the same thing about six months ago and i replaced the thermostat and its been fine ever since. the thermostat is located on the back of the engine below the intake mani. on the left side of the engine. the thermostat housing is outside the engine kinda on the corner. shouldnt be that hard to find it.

 

I can only share this anecdotally...

I had a problem on my '98 Civic DX where my oxygen sensor blew due to a bad catalyst (it rusted through due to Colorado winters) and it, in very short order, started to burn into the head gasket (although this was around 273K...what do you want, really??). It happened in a matter of about 3 weeks....and all the symptoms you have described manifested themselves. No water in the oil either, but driving it over about 55 would make the coolant blow back out through the reservior. Also when you started the car you could hear a bizarre sloshing sound...so I knew what I was in for. Never blew the gasket, and even Honda service had a hard time diagnosing it at first because the gasket had only just started to go. But after the comp test they were sure it was cylinder #1....I told them to replace it to the tune of about $750. The car has 363K on it today and runs like new......well worth the dollars to fix it if your car is in otherwise good shape.

And it very well could be something cheaper......let's hope so!