Hi, I was told by the dealership mechanic that I have a “death rattle” in my Ford F-250. The check engine light came on about 3 months ago for a miss fire. I replaced the plugs and coils on both misfiring cylinders. Light gone. It came back on yesterday, so I took it in. They told me it was a miss fire, and that the rattle I also reported hearing was the so called “death rattle “ . To me it sounds like a loose heat shield in the front of the truck, but I only hear it when I hit about 2,000 RPM, and it’s especially loud when I’m hauling heavy loads.
Is this a thing? They couldn’t even tell me what’s exactly wrong, just that they could fix it for $4 k, and it would eventually still fail, or put a new engine in for $7k. 5.4 L engine