The coolant sensor is ok

The symptoms i'm having are:
Starter cranks with normal full power
Engine does not fire unless accelorator is depressed and engine cranked for approx 20-30 seconds.

When started first time after sitting in cold for over 5 hours
engine runs as if only a few cylinders are firing until engine runs for about 2-5 minutes then runs smooth with no hesitation or adverse problems.
Once warmed up it starts fine no hesitation.

I am looking specificly for something to maintain the temperature around the top engine area to prevent any condensation freezing around the injectors.

I know they have a block heater - oil warmer, but are there any other accesories or chemicals to be used with gasoline that would help prevent the freezing in the injectors? any make-shift ideas?