1999 corolla p0420 p0446

[toyotalife]

Hi i have a general question about these codes and trying to diagnose it.
I've had the evap emission code p0446 for about 3 years now and have not had any issues with it. Also the p-0420 came up as well
My car has been stalling when I start the car, it happened once a few months ago now its getting more persistent to almost once per day.
The car would start for 3 seconds shake and then turn off, start for 3 seconds shake then turn off.
Eventually after turning the key and trying for 10-15 minutes it will start and run .
I recently had to take it on a long drive and didn't want to turn the car off in case it didnt turn on.
I left the car on when i added gas and after a minute of pumping the car stalled and shut off

Just trying to diagnose the issue as i dont have much cash for another car and my little 99 trooper has been good to me.
In my research the things that have popped up related to stalling were.
Fuel Pump
Charcoal canister
Timing Belt
vacuum switching valve

Any help to help me pin point exactly what it could be would be very grateful

 

[Imperial73]

The po446 is an evap code.
All the codes from po440 to po459 are all the evap codes. They need to be fixed but don't cause stalling.
My car stalls when I put in gas too. Don't worry about it.
The po446 could be just a bad gas cap. If you replaced the gas cap and still have a code, then it's a purge valve, vapor cannister, etc.
but it doesn't affect the running of the car.
The important code here is the 420 code. It is bank 1 catalytic converter. If your car has less than 140k on it, it's probably an O2
sensor. If your car has over 140k, it's probably your catalytic converter. When it clogs, your car can't breathe and will shut down.

If the car still runs, you can buy time by making sure your air filter is clean, making sure the spark plugs are clean, and putting in a fuel injector cleaner like Seafoam. It might clean out the cat somewhat and buy you time.
eventually though, you might also get a po430 which is bank 2 cat and you will probably need to replace the catalytic converter.