Hi, thank you for choosing Justanswer, I look forward to helping you resolve your issue. No, you should have received a check engine light being on for a peripd of time first along with the vehicle running rich and have several diagnostic codes set in the computer. If your vehicle just shut off for no apparrent reason it is more likely you have an ignition system problem rather then a emmission system problem.

First off you can't over fill the gas tank. So what your saying is the engine keeps running and even though you have it in drive and you are giving it the gas the vehicle continues to slow down until you come to a stop and giving it the gas only makes the engine rev up but the vehicle does not move, like it is in neutral?

Do you have the 2.0 or 2.4 engine?

Does the check engine light come on when this is happening or have they checked for DTC's and if so do you know what they are?

Yes

Normally you would have the check engine light on prior to a DTC being set but not always. i would ask them to check for codes. Without any codes they are making a heck of a leap to blame the charcoal canister. All it does is store the fuel vapors and via the purge solenoid route the vapors to the intake manifold to be burnt during normal combustion process so even if the canister were saturated then the purge valve would always be open allowing the vapor to be purged and routed to the intake. Your problem sounds more like there is an issue with the transmission range sensor where for what ever reason the computer thinks you have put it into neutral. An easy way to verify the canaster is not the problem is to bypass it. Remove the input hose and output hose and hook them together. Now the system will believe there is no fuel vapor in the canaster.

Your welcome, come back and let me know what they come up with or if you need more help after you talk to them.