Owners/service Manual problems of the 2008 Chevrolet Silverado 2500

First time I got headache and dizzy in 5/28/2010 doctor put me in hospital over night and found nothing did not know it was carbon monoxide poisoning and to test blood. Had exhaust leak fixed by dealer ship on 7/02/2010 coworker said he could smell exhaust in cab that's why I took it in I could not smell it. I have had a lot of trouble with exhaust system filter light coming on with engine power reduced. Taking back to dealer ship. They said it needs to be put in regen mode manually, on 12/17 2012 is started to pass out on road doing 35mph started to loose vision, headache, dizzy felt like my heart pounding in my chest and that's not all more to list. But started go to doctors on my symptom's for over a month taking sick tome and vacation time. When I realized every time I got in my work truck it all started over again. So took back to dealer for exhaust leak and they said was leaking at turbo and down pipe. Said they fixed it by tightening clamp. Got down the hwy 15 miles and started happening again. I rolled the windows down and drove home blood pressure 170/110 that's another thing it does. My boss took it in to a diesel truck specialist and they said the down pipe is cracked and leaking and advised to fix or drive it with the windows done. They started to send in all our local trucks to get tested and we found 5 trucks leaking. I'm sure there are a lot more out there. We had another guy crash his truck from passing out at the wheel before I found the defect in the truck. Now the company knows why he crashed. This issue is in 2007 and 2008 models diesels.