Hang in with me here. I need to give some background on the issue(s). I've taken it to 5 different shops, and have gotten conflicting reports, and no solutions. The car has 170k miles.
The first problem I experienced with this car was overheating while not moving at 40mph or above. When I would stop at a light, or in traffic, the car would get hot. If I was moving at a decent speed, the temperature would come back under control.
The first time I brought it in, NTB couldn't really see any problem, so they reccommended a coolant flush, thermostat and radiator cap replacement. I did that, and it seemed to deal with the issue for a few weeks. After that, it slowly started acting the same way.
At that point, I brought the car to a Honda dealer, and was told that the head gasket needed to be replaced. Looking for a second opinion, I brought it to a small shop run by a buddy I trust to tell me the truth, and he could not find any problem with the head gasket, and said the symptoms I described (even though he didn't see them) were inconsistent with a head gasket problem, so he replaced the thermostat again with an OEM part, and again, that dealt with the overheating for a while.
The problem started slowly coming back, and it also started running slightly rough when I would first start it up. After 5 seconds of idling, the car would run smooth. All of a sudden one morning, the car ran so rough at startup that it would not stay running so I had it towed to another NTB. That shop also told me that the head gasket needed to be replaced, so again, I brought it to my buddy, and as soon as he tried to start it, it behaved nomally. It started normally, and it would not overheat, even after hours of operation.
I left the country for a few weeks at that point, and had my Buddy keep an eye on it. He ran more tests, and found an error code indicating that the Electronic Load Detector was faulty. He replaced it, and didn't have any problems with the car while I was gone. I picked the car up two days ago, and it ran fine, with the exception of again running slightly rough when I would start it, but again it was for only 5 seconds.
This morning, the car would not start. I towed it to a Goodyear, and upon arrival, it started and ran just fine. They don't see any issues with the head gasket, and are going to keep it overnight to see if they can duplicate the problem tomorrow.
So at this point, I've had 5 shops look at it. Two of them replaced the thermostat. Two of them said the head gasket needed to be replaced. Two of them said they don't see any problem. That seems like fuzzy math, but my Buddy replaced the thermostat even though he didn't see any problems first-hand.