While scavenging parts off my donor tercel, I came across the charcoal canister.... It's in poor shape. I tested it, and when you blow into the inlet, there is no flow of air. According to the manual this indicates that the canister is bad. I tried purging the filter, but nothing came out, only clean air.
The big vaccum hose on the canister was broken. You can see it in the picture. This would cause the carb to have access to the outside air, whenever the valve is open. I checked the other tercel, and it's vacuum hose was broken too.
Here is a picture:
