mitsubishilinks.com, 89 montero manual, vol 1, MPI section, "Testing engine coolant temp sensor" section.

Can't remember what the spec is at that range, and you need the manual .pdf anyway.

Acrid is a sign of leanout. Bad fuel press regulator, fuel pump, fuel filter, pickup sock in tank to pump. Possible blocked injectors. If ect sensor is bad, also will cause leanout at startup, and no start in cold conditions.

ALso possible vac leak, spray mani joints and hose connections with propane and see if idle rises.

Not responsible for advice not taken...