Took in to have shocks checked and mechanic found exhaust manifold to be cracked over 3/4 of the way around betwee the middle two exhaust ports. My brother in-law suspected a leak as I was putting boat away over one year and 25000 miles ago. I do not ever remember the truck sounding any different and the manifold is under a heat shield so I never spotted the crack. I have always smelled exhaust but thought it was comming from other vehicles. I frequently make long trips in the truck and have had to fight to stay awake that I now know may have been due to carbon monoxide poisoning. I had the exhaust manifold replaced by my dealer who probably has saved me from further harm or even death. They would not replace the manifold under warranty. I have to wonder why they had a replacement manifold in stock if this is not a common occurance. I kept the manifold and will send it wherever you want if you would like to examine it to determine what caused the crack. I am an engineer and suspect that an approximately one inch manufactured hole in the heat shield allowed water to hit the manifold and thermal shock caused what appears to be a cast iron manifold to crack where it did. One more inch of cracking and the manifold would have broken in two.

- Chattanooga, TN, USA

White smoke would come out of the exhaust pipe whenever consumer started car.

- Larkspur, CA, USA