So I just got a 9c1 a couple of weeks ago. Last Saturday, I drove about 65 miles and got down to about a quarter tank and refilled it to about 1/2 a tank. I put the cap back on, turned the car on and was pulling out of the station and then it stalled out as I was pulling into traffic . Had to get a bunch of people to push it out of the street back into the station. I called my dad up (was a couple of blocks from home fortunately) and he came and checked it out. The car was cranking but it wouldn't start, then he started giving it gas while starting and it started up from the seeming dead. As he was pulling out again, it died again, and he started it and was able to drive back home, uphil 2 blocks. We let it cool after parking and went back out and I tried starting it and it started without a hitch. I scanned the car with an OBDII and it came up with the following codes:
P0036 Oxygen Sensor Heater control circuit Malfuntion (downstream)
P0141 Oxygen sensor heater circuit Malfunction (downstream)
P0446 Evaporative emission control system vent system performance.

I messed with the gas cap and it seemed to be fine. I deleted the CEL.

This morning I warmed the car up, and drove about 3 miles. All was fine, until I made a left turn home and brake and gas pedal sunk and the car stalled out and ran into a corner curb. I had to give it gas again and drove it around the corner to my house (once again I'm lucky this happened close to home). We had to start the car up maybe five times to get it up the hill and park it. By the time we were done the car would crank but would not start. My dad and I postulated that it might be a problem caused by when the car was warmed up. My dad and I let the car cool down for a bit, then went back out and tried to start it again. It started but instantly died out. I then asked my dad to rescrew the cap and it worked, then I told him to take the cap off and it stalled and wouldnt start up. We've been in and out to see if it would start again. Again, I ran a scan on the car the codes that came up were:
P0036
P0446

I went out and put some Gum Out Winter formula in the tank to see if theres some water in the tank or anything and will let it sit overnight. Anyone have any ideas or suggestions or similar experiences? I suspect its the fuel pump or a hole in the fuel line.

This thread sorta had the same gist, but I didn't read a solution in there.
https://www.gmforum.com/2000-2005-90/stalling-after-gas-fill-up-update-201769/

Is that the 3.4L motor (3400)?

3.8 Liter or '3800'

Kind of sounds like your HVAC purge valve is stuck open. The car is running rich, that'* why it'* stalling, the O2 sensor is over loading. And that'* why giving it gas allows it to start. Flooring it shuts off the injectors.

So will all of the codes disappear when this is fixed? How much would it cost to get this done?

You might just need an EVAP solenoid. The oxygen sensors may need to be replaced, and if it was driven this rich long enough, you may have some stuffed cats. However, your car is generally fine and shouldn't really cause any more problems after this. An evap solenoid'* cost is in the single digits at a junkyard, and it should outlast most other parts on the car.

I don't know what happened to your current solenoid, but you should probably clean out your intake with a few cans of Seafoam. It took 3 cans to get a good, clean exhaust without as much white smoke on the Alero.

So now the car just won't start and you can hear the fuel pump click and no gasoline come in. I guess theres definitely something wrong with the gas getting to the fuel pump.

I went to a mechanic and I told him I was having a problem with the evap system and he just quickly told me "NO" without listening to any reasons. I'm a bit frustrated with all of this because my dad just wants to put it in a shop. I know we're gonna have to pay some inflated cost, but how much do you all think this should cost to fix?

My suggestion is to find a new mechanic. Replace the evap purge solenoid/valve and go from there. Its a 3 minute job and $30 tops brand new. If that doesn't fix it, investigate the condition of your hoses and go from there.

Let'* have you post in the Wanted section of the classifieds, and someone out there should have an EVAP solenoid. I'm going to check with a few people here and there, and the swap is excessively easy.

Then, if the oxygen sensors and cats are shot, you may go to a shop. The thing is, they're going to charge you everything in the world to do that. I suggest you buy a $20-40 cat from eBay and ask a shop to install that instead. Pick a good shop because you also need to get a front (and a rear) O2 sensor and just go ahead and plop those in there in between welding. Maybe they could do it while you sit and relax. One 7/8" wrench, box end is fine, and you're free & clear.