First off I want to say I am learning as I go with this vehicle. When i first start the truck to warm up, it takes about 15 secs before you start to here the rattling and it sounds like it is coming from under my seat. It does eventually go away, I figured she's old even I have trouble gettin going. Another thing that bothers me is how long she takes to warm up when it's really cold out. We have been in the single digits I let her run for 45 min and she never got warm the temperature gage on the dash never made it past the 130. I had to push on the gas until my RPMs was at 2 for 15 min and it only got to the second line. Any ideas maybe they go hand in hand.