My brothers truck has been having some problems since its gotten cold here in wisconsin. Its plugged in and has anti-gel fuel additive in it. It starts up perfect and will idle about 20 minutes then it sounds like its missing and idles really rough then dies. Only fuel mod is an airdog. This has only happened three times on the coldest nights. it has p0216 code. Also it dont sound like the grid heater is cycling correctly. after it dies it will restart but only runs for a few seconds and then dies. Any suggestions?? Thanks for reading. Its a 1999 year

 

Does he run 2 stroke in the fuel?