Or so here's the deal:
I posted a thread on how my car would run cold when on the highway but that was in the winter. Everyone suggested that I replace the thermostat.I had it replaced when I had the water pump replaced. That seemed to fix the problem ,but over the weekend I was on the highway on a 90 degree night when the tempature gauge went right to the big C. I was driving down rout 86 to the city and the thermostat stayed on cold the entire trip. It did show that the engine was warn for the 1st 20 min of the trip. ANY suggestions?
Thanks

 

i have the same problem but it seems that mine works but not all the time so i dont know

 

I had a similar problem with my old instrument cluster it would sometimes stay on cold even though I was running for a long while. Other times it would be at the normal halfway range. I swapped out the old cluster and replaced it with an SE-White Gauge one and now it works perfect.

 

I dont think its the instrument cluster, because if I turn on the heat at 80 degrees, the air still cameout cool. So the heater wasnt working either? However, when I drove the car this morning it warmed up and the heat was working again. This was city street driving, not highway. Could this be a problem with the heater core?