I have an 03 Impala 3.4L. On very cold days my temp gauge barely hits the first mark and then fluctuates up and down. It takes a long time for the car to warm up. On warmer days it goes higher. I believe this is causing some other problems like lower gas mileage and some surging when going up hills. I also have a PO401 code. The thermostat is not easy to get at but I do have to remove the throttle body to clean the EGR port and this looks like it will give me access to the thermostat. I would also like to replace the pipe from the manifold to the EGR valve. I have all the parts needed to do the work Any help, ideas or tips will be much appreciated

 

Any Help? I have to pass emissions test by end of month.

 

Problem was completely blocked EGR port in manifold. Had to remove throttle body and EGR valve to get to it. Thermostat can be changed by removing throttle body to gain access need short 13mm wrench and patience to do thermostat change this way. EGR tube can be done with a 22mm crows foot and some creative thinking. Thanks for all the help