Ok my car is pretty much all stock. Its a 91 with about 30k miles original on it. I have a few bolt ons and exhaust on it but no engine mods. I took it on a longer trip a few weeks ago and i noticed at about 45 miles away from home that the temp gauge is reading towards the warm side. I pulled over and checked the coolant and all ok. Drove the rest of the trip while keeping a close watch on the situation. Once home i changed the thermostat to a 180 and flushed the system. Also replaced the fan clutch. Now still having the same problem. Runs warm on the freeway, normal to low at lower speeds and in traffic. WTF?? Anyone seen anything similar?