2006 chevy venture will not stay running when I start it if I take my foot off from the gas peddle

find and fix the vacuum leak

The throttle body needs a thorough cleaning. Brake clean and a toothbrush will do the job. Clean the back of the throttle plate as best you can.

might be plugged fuel filter or maybe idle air control valve or severely plugged air filter

OBD2 code scanner will make you know what problem cause the engine light on.

Some models have to be retaught how to idle once the battery dies, so you need to start the truck and feather the gas peddle to keep it running and do this for a few minutes, the computer has to relearn how to idle the engine.

If it starts for 5 seconds out less, and you notice a security light on the dash, go to this link for answers. Gm are notorious for failing antitheft systems http://vatspasslockpasskeysecurityhelp.yolasite.com/

Vacuum lines are broken, cracked, or removed? I had the same thing in my Lincoln, ended up being 2 cracked vacuum lines and the Mass air flow.

That sounds like a faulty brake light switch located down on the brake pedal lever under the dash, or a damaged wire at the wire connector to the brake light switch. Here are some images of what the brake light switch looks like to help assist you.

While driving my 2006 pt c. All the warning lights come on, the dashboard needle gauges go down, and the car looses power. I pump the gas peddle and it goes back to normal.

the carburetor needs to be rebuilt, it sounds like the accelerator pump is bad which is in the carburetor and will be replaced when it is rebuilt. I hope that helps you out!