Fluctuating temp gauge

I have an integra 1992 gsr I am running across a problem with my temp gauge fluctuating. The temp gauge would stay in the middle at normal operational temp (I think?) then when I accelerate it would drop on the cool side. I am not sure what is the problem. Also my rpm is reving at +1000rpm and I cannot get my rpm to drop to 650rpm +/_ 50 rpm. Anyone come across this problem. Recently, I replaced the head gasket.

Your idle problem could be indicative of air in the cooling system, I suggest you try “burping” it. As for the temp gauge dropping under acceleration and/or higher speeds, that’s typically a sign that your thermostat is stuck open.

Assuming there is no reason to assume anything went wrong w/ your head gasket install I would suggest you pull out the thermostat and test it. You may even find that just by looking at it once you remove it that it’s stuck open. If it needs replacing, replace it, properly rid the cooling system of all air, reset your ECU and see how it runs.

Problem solved. It turned out that I have vaccum leak. One of the vacuum hoses near the intake manifold was not plug in. I probably missed it. If anyone come across this problem make sure all the vacuum hoses are plugged especially the one near the map sensor because that area is very easy to over look.