I have been on a wild goose chase with my wife's Rav4. The check engine, VSC and 4WD lights are on and the only code I get is P0441. I have replaced the charcoal canister and the purge valve under the hood and the problem still exists. I have had it in the shop and they did a smoke test on it and they found no leaks. Any advice on what to look at next? A couple people at work said I should replace the PCV valve and see if that helps. Her vehicle also burns oil and it doesn't get the best gas mileage anymore which a couple of people say could be the PCV vlave. Overall, I'm at a loss since the mechanics said to replace the charcoal canister and the purge vlave and I'm still having trouble.