I own a 2001 Montero, and recently the temperature gauge started acting up. I immediately replaced the thermostat, which wasn't the problem. I took it in to the shop, and they replaced the temperature sensor. Five minutes after leaving the shop, the temp gauge pegged to Hot again, and then immediately back down. The shop tells me that temps are normal when hooked to the scanner, even when it's pegged on hot. They kept it for a day to run some tests, but are dumfounded. They don't know what the problem is, or how to rectify it. Please help.