I have an exhaust leak.
The exhaust manifolds are known to warp on these engines, causing an exhaust leak. This is typically most noticeable when the engine is cold, before the metal heats up and expands. The only solution is to replace the manifold(s). However, any part of the exhaust system has the potential to leak. So, before condemning the manifolds, I would have your truck’s exhaust leak issue inspected firsthand by a professional. I suggest giving YourMechanic a call.