When the temperature outside is 20 degees or lower the engine will not start. I have to push down on the gas pedal a liitle to feed it fuel, then it will start. Until the engine warms up it has a tendancy to stall. It is a 1996 Dodge Grand Caravan with a 3.0 engine.

Try this. Find the ambient temperature sensor. The one that reads the outside air temperature. Put an ice pack around it and try turning it back on and hot the accelerator. The sensors are usually around the front of the vehicle.

put the accelerator pedal down at least twice ? While cranking the engine ? key on ? what ? Your vehicle has electronic fuel injection ,not a carburator . Pushing the gas pedal doesn't do anything The only thing if pushing the gas pedal to the foor an holding it there will put it into clear flood mode , shutting off the fuel injectors .

The fuel pressure and fuel system needs to be inspected.
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I suggest you few helk links.Click the link below and follow its troubleshooting procedure:------------------Pushing on the gas pedal, but the car slows down? Gas pedal to the floor and the car slows down? http://technoanswers.blogspot.in/2012/02/pushing-on-gas-pedal-but-car-slows-down.html
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Car dies when gas pedal is pressed? http://schematicsdiagram.blogspot.com/2011/12/car-dies-when-gas-pedal-is-pressed.html
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Car won't start without hitting the gas pedal? http://schematicsdiagram.blogspot.com/2011/12/car-wont-start-without-hitting-gas.html
-------------Car only starts when gas pedal is pressed? http://technoanswers.blogspot.com/2012/01/car-only-starts-when-gas-pedal-is.html
----------1999 Ford F-150 Idles rough and quits when gas pedal is pressed less? http://technoanswers.blogspot.in/2012/01/1999-ford-f-150-idles-rough-and-quits.html
----------Delay starting on Toyota Prius? http://schematicsdiagram.blogspot.in/2012/02/delay-starting-on-toyota-prius.html

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These will help.
Thanks.

Have you checked the fuel pressure with a gauge yet ?

sounds like the carb may have blocked jet(s), worn diaphram ,air leak ,incorrect fuel/air mixture any of these will cause your problem , have the carb overhauled

Check & replace ambient air temperature sensor

There were some issue as to outside temperature effecting the starting operation of some Sentra's. A trick that I would do is remove the fuel pump fuse and spin the engine over continously and pulsing the fuel by touching the fuse (or tap the fuse against the contacts) to the contacts and the engine starts. Its tricky but it works. The idea is to clear the engine of raw fuel. The vehicle can be put in clear flood mode by holding the gas pedal to the floor while cranking the engine. This sometimes works also.

First, disconnect neg battery cable 10 minutes and reattach to clear codes.
Lean condition means it is not getting same fuel as other side of engine.
Since you had it scanned before, try Autozone to see if new results.
You might try a TPS switch which regulates spark and fuel feed. At lower speeds EGR starts to open-you should have code for a problem there.

How old is your Battery? at the Temp. Stated above an Older Battery even though Good may not have Enough Cold Cranking Amps Left to Kick her Over.

I'm leaning toward a bad sensor, as in throttle body temperature, or coolant temperature sensor. The smell of too much fuel is probably from pushing pedal to start, which shouldn't be necessary on a fuel injected vehicle. What does it do if you leave your foot off the gas pedal during start? As far as fuel filter goes, if it hasn't been done in a while, I'd do it anyway just as preventative maintemance if nothing else.