Have a 2014 4.3 Silverado with around 180k miles. About two weeks ago I noticed that whenever I’m driving (any speed) and press the gas pedal halfway or more for about 5 seconds I notice it starts to go from normal 210° to around 220° once I start to see it go up I let off and it goes back down. I could let it idle with the ac on and it’ll never go past 210 only when I step on it even with the ac off. The coolant is always at the top, the fans turn on when the ac is on , I haven’t seen any leaks, the radiator hose is hot after driving and radiator doesn’t have too much build up on it from the outside . I’ve replaced the thermostat twice in the past year and a half because both times they went out and marked 0° the whole time while driving causing my fans to always stay on (I just disconnected the battery for 10 min and after it would only mark around 100° but I only did it so the fans wouldn’t turn on, and It ended up being the housing) I also don’t think it’s the thermostat because otherwise it would go up and down like the other times And it only goes up when I know it will (when I floor it a little bit). Any idea what it could be?