I recently bought a 98 silverado Z71 ext cab with 93k miles on it. It runs great but when you first start it and drive, the temp gauge will shoot all the way up to red, the check gauges light comes on, and then the gauge goes back down to 210 and runs between there and 3/4 on the gauge. The guy I bought it from said he brought it in and had it hooked it up to a computer and it said there was nothing wrong. It does this every time I drive it. I don't know if the engine is actually getting that hot or if it is a malfunctioning sensor. I am a student with little $$ so any info on this topic will be appreciated.