No engine power at startup

[trade14u]

I have a question concerning LOW or NO power from the engine at initial startup:

I first must mention I have OLD GAS in the tank...very old...that I plan to drain this week.

That said, when I first fire up the Pcar, if I pounce on the gas pedal, the engine wants to die; that is until its nice and warmed up. This weekend, I had the car in the drive and wanted to pull it back into the garage. I had to wait a good 3 minutes before I was able to pull the car up the drive into the garage! There was NO GO from the engine until it was warmed up - just a slow creep up the hill. Once she's purring for a while, there's no problem... I can put the pedal to the metal without even a sputter.

What do you think is the problem? The gas? Worse?

Brad