Where is the canister located? It's like $100 right? I keep getting erratic idle and I already did the purge valve. I always top off when I get gas and I think that's what caused it. How hard is the canister to take off?The purge valve is located on the evap canister which is by the rear of the car/fuel tank. I only replaced the valve and it did not fix my issue at all. I would suggest replacing the entire canister as it is only a few dollars more and includes the evap purge valve and you may have better luck.