I hit a deer about 2 years ago with the front end of my truck took it to a body shop and they were supose to fix it. When I got the truck back my enging light was on. I took it to advance and they pulled the code saying that it was taking to much time for the engine to heat up. So I went to my gm dealer and got a new thermostat and a new temperature sensor and installed both of them. I took the truck down the road for about 20 miles in the mid of summer and my temperature guage on the dash wouldnt get over 175 degrees. I then went and got a snapon obdII scan tool and hooked it up and drove the truck back down the road for 20 miles and the guage on the dash was reading correctrly to what the scan tool was reading. Would could be causeing my truck to not warm up fast enough?