My 99 Caravan 3.0 engine is refusing to start now that winter has arrived. Overnite temps here are in the -15C range ....and as soon as this cooler weather arrived, the engine will crank and crank and crank, but not fire up. Code reader says P0300 "random multiple misfires". At one point, I plugged in the block heater overnite and added gasline anti-freeze, and in the morning the engine did fire up ...although reluctantly. Then while driving, it started to sputter (misfires??) and the check engine light came on. Now, for the last week or so, even though I have kept the block heater plugged in, and have added more methyl hydrate (gasline anti-freeze) to the fuel tank, it refuses to start. It started and ran fine until the weather cooled off. Any suggestions? .....anyone????

 

Have you considered the spark plugs? How long have they been in there? Is the battery and it's connections up to the task?

http://www.obd-codes.com/p0300

 

Okay ....that sounds like a good place to start. I've gone to the link you posted and will start with that shopping list of possible causes. Still doesn't make sense that this would only begin to happen after the weather turned colder ....or do you figure that's just a coincidence??