um no. p0446 isnt "just a gas cap"

here, striaght from SI..

This DTC tests the evaporative emission (EVAP) system for a restricted or blocked EVAP vent path. The control module commands the EVAP canister purge solenoid valve Open and the EVAP canister vent solenoid valve Closed. This allows vacuum to be applied to the EVAP system. Once a calibrated vacuum level has been reached, the control module commands the EVAP canister purge solenoid valve Closed and the EVAP canister vent solenoid valve Open. The control module monitors the fuel tank pressure (FTP) sensor for a decrease in vacuum. If the vacuum does not decrease to near 0 inches H2O in a calibrated time, this DTC sets.

this is something you probably wont be able to fix yourself. you may actually want to take it to a dealership and have them look at it.

 

*sigh...damn it...

 

check your axles, i recently had a vehicle come in and it had a bad axle, the cv joint was locking up at one point in its rotation causing the whole thing to be trown of balance.

 

mine did the same until i swapped it with the prothane mounts now i dont get any wobble