Hello, I have a 1999 suburban 2500 with the L29 big block, and have some strange cooling "issues". In normal driving, my guage reads at a tick or two below the bold 210°F mark. When I get on the highway, my temps are a hair below the bold 210° mark. But when I get off the highway and end up at a stop light, my temps are slightly above the 210° mark, and will stay there until I drive again and hit speed. My OBD2 sensor reports "exact" temps, but in strange increments (192.2, 194.6, 197.6, 199.9) never in-between those numbers. What could be the issue if any? Is this normal for the 454? Any insight is appreciated.