Did fuel pump at 160,300 miles. Why the insulation on the bed?

 

i think its a fire blanket maybe for the fuel tank but not sure

 

Might be just there to stop vibrations/noise.

 

aren't the cab "blow-by" vents located in those areas on the cab side? probably to cut down on the sound traveling through the vents into the cab.

 

Yea, there are vents in that area. A fire blanket wound span the whole width and be on the cab not the bed

 

Stick a magnet to the inside areas of the bed where the tape runs.If it doesn't stick in some areas I would suspect the previous owner used the tape as a backer for body filler.
Also inspect the back of the cab for any scuffing or slight dents. The bed may have been contacting it and rubbing due to misalignment and that was a quick fix.
Only other thing I can think of is the bed was off for painting and someone put tape there to protect it while standing the bed on end on a couple 2x4's.

 

x2 on this. Truck may have been fixed and they couldn't get the bed to align properly, What kind of spacing do you have between bed and cab? I can almost fit my hand in mine.

 

No Bondo or accidents. Original owner knows nothing. No vents on the cab. Space is normal.

 

Maybe the factory just put them on all beds.