Exhaust spews liquid and black soot on start up occasionally.

[ChrisParker]

How can I fix this or is it unavoidable?

[BradMph]

Mine does this occasionally also. Though it is not a lot but this is what I found it to be. Depending where you live and the condensation that exist, this can build up inside muffler pipe. If your truck sits for some time and you go to start it, the moisture that built up in the pipe will come out and drag some of the residue that is located on the inside of the pipe. Mine would leave a black spot sometimes on cement, but not a big pile of it, just a little from the moisture exiting the pipe. I imagine hi humidity areas can accumulate more then others, but this is what I came up with the reason. You may check also if your burning rich. Check your plugs for black soot or unburned fuel or what not. I don't know what your engine has for after market items, but mine is modified and it will spew a little stuff occasionally.

[ChrisParker]

That sounds about right. I live in Florida near the ocean, so this all makes sense. Thank you