i heard something somewhere about a charcoal canister that can cause this, it happens from over filling the gas tank and causes a varpor lock or something that makes the engine stall out. yeah pretty out there but heard it was a common thing.
not saying this is your problem but a possible cause.
from another 4runner forum
"- Lots and lots of Toyotas (and Lexuses) have had our problem, and there's a TSB for it (can be found here). Older Toyotas displaying codes P0446 and P0441 likely have a design flaw in the evaporative system. Fuel backfills a charcoal canister that's part of the emissions control system, due to the canister's poor location. This causes the valve inside the canister to stick and the pressurization in the emissions system to fail. Also, the charcoal will no longer be able filter out hydrocarbons, so the car will fail emissions tests in states with inspections.
- Most people first try replacing the gas cap (since that can cause these two codes, as people above have pointed out). They also try replacing an $80 valve next to the canister. Unfortunately, these cheap fixes won't work if your vehicle has the design problem.
- Toyota refuses to pay for the repair, even though it's a design problem.
- The canister costs somewhere between $289 and $600 for the part alone. I did find one guy who pulled his canister out, drilled holes in it, washed it out with soap and water, unstuck the valve inside, dried it with a hairdryer, patched the holes, then reinstalled it, but he was a pretty serious mechanic. Unfortunately, I also found several people who bought new canisters on their own, attempted the replacement, then gave up after hours of work and had to take it to someone to get the thing put in correctly. I think this may be beyond DH's automotive DIY comfort level.
- Because it's a design problem, the new charcoal canister will eventually get destroyed as well. Fortunately, it seems to take between 60,000 and 100,000 miles to destroy a canister. People suggest stopping short of a full tank every time you fill up to reduce the likelihood of gas backfilling the canister.
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