I recently posted I was smelling exhaust fumes in my cab at auto start warmup. I depressed the re circulation button and the smell does not enter the cab. Is there a setting at auto start that will allow this re circulation button to stay on? Also yesterday for the first time I noticed a large amount of white smoke from my tailpipe for the first five minutes of driving and then it stopped. I use archoil 6200 fuel additive. It has never happened before even in the coldest weather. Is it a problem or normal. I've never seen white exhaust since I bought the truck new. It is a 2015 with 10,000 miles. Can anyone help. Thanks.