Smell of gasoline fumes at rear of car but no leaks showing. Gas tank has been removed and replaced with all new gaskets, filler hose clamps etc. Could it be a bad vapor canister or canister valve? Gas cap has been replaced.

did you check to see if your gas cap is missing?

Gasoline smell Ford Ricks Free Auto Repair Advice

The FSM is clear on this. each hose and fitting must be air tight.
or the the car vents gas fumes full time, and the EVAP ECU tests
(monitor) make sure this all works.
you can just look at the left and right side above rear tires. and see
if your hands are small enough to fit here. Id bet not.
some mech, report, the tank can be tilted down at front (drained fuel)
and gain access.
keep in mind, you get fuel siphoning at any time. do not open the system, with fuel in the tank, and then drive to autozone,
i loosen the gas cap so that pressure can not build in tank.
expanding fuel can push fuel out , during a filter change. very
dangerous in a garage, and you gone.
it's just a vent hose, you can see, it and what needs to be done is really obvious. given you arms sides and lenght.
my fsm states, " TANK pull"

Removal & Installation

1. Relieve the fuel system pressure and disconnect the negative battery cable.
   
2. Remove the fuel filler cap from the fuel tank.
   
3. Have a Class B fire extinguisher near the work area. Use a hand operated pump device to drain as much fuel through the fuel filler neck as possible.
   
4. Use a siphon to remove the remainder of the fuel in the tank by connecting the siphon to the fuel pump outlet fitting.
   CAUTION Never drain or store fuel in an open container because there is the possibility of a fire or an explosion.
   
5. Reinstall the fuel filler cap.
   
6. Remove the rear seat cushion from vehicle (if so equipped).
   
7. Disconnect the fuel pump motor connector and sending unit electrical connectors.
   
8. Disconnect the wire harness grommet and harness through the vehicle floor pan.
   
9. Raise and safely support the vehicle.
   
10. Remove the fuel filler hose clamp from the filler neck assembly.
    
11. Remove the fuel breather hose clamp from the filler neck assembly.
    
12. Remove the fuel filter inlet hose clamp and hose from the filter.
    NOTE A small amount of fuel may be released after the fuel hose is disconnected. In order to reduce the chance of personal injury, cover the fitting to be disconnected with a shop towel.
    
13. Remove the fuel vapor clamp and hose, and fuel return hose clamps and hose from the respective fuel lines.
    
14. Using a suitable transaxle jack, support the fuel tank.
    
15. Remove the fuel tank retaining bolts and lower the tank.
    

To install:

1. Reconnect all fuel hoses, lines and the fuel breather hose to the fuel tank.
   
2. Place the fuel tank in its proper space using the transaxle jack, Install the fuel tank retaining bolts.
   
3. Remove the transaxle jack.
   
4. Reconnect all fuel hoses, lines and the fuel breather hose to the fuel tank.
   
5. Install the fuel breather hose and hose clamp to the filler neck assembly.
   
6. Install the fuel vapor hose and hose clamps. Install the fuel return hose and hose clamp to the respective fuel lines.
   
7. Install the fuel filter inlet hose and hose clamp to the filter.
   
8. Lower the vehicle. Install the wire harness and grommet through the vehicle floor pan.
   
9. Connect the fuel pump motor and the sending unit connectors.
   
10. Install the rear seat cushion. Reconnect the negative battery cable.
    

"

A rusted out fuel tube on top of fuel tank,
rotted & leaking hose or bad Evap System
Solenoid

If you smell it,it is leaking,fuel or fumes

You can check to see if the hose clamps are tight on the filler neck and the breather hose ,i would also check the fuel filter under the car rear near tank for leak's as this can give the smell of fuel around the rear of the car . when you open the boot of the car do you smell fuel or is it only on the outside of your car????? hose clamps and fuel filter = outside of car. smell in side of trunk (boot ) fuel return line hose clamp might just need to be tightened up. you might have to remove the rear wheel and inner wheel cover to get to the Fuel tank filler to check the hose clamps.

I would check the gas cap to make sure the gasket is seating correctly on the filler neck. Also check, if you can, the filler neck from the gas cap down to the tank. If it is damaged, it could seep gas fumes. If you see no other signs of an obvious leak on the garage floor, it's likely a gasket issue in the fuel fill side of the system. It does not take much fumes to smell it strongly.

TO REMOVE FUEL TANK YOU FIRST RELIEF FUEL PRESSURE.THEN YOU RAISE THE VECHICLE AND SUPPORT ON JACK STANDS.THEN YOU DRAIN FUEL OUT OF FUEL TANK.YOU CAN GO TO ANY AUTO PARTS STORE BUY A SIPHON.DONT SIPHON GASOLINE WITH YOUR MOUTH.SWALLOWING GAS AND FUMES COULD BE FATAL.WHEN ALL FUEL OUT THE FUEL TANK.REMOVE THE FUEL FILLER.DISCONNECT THE ELECTRICAL WIRING TO FUEL TANK.THEN DISCONNECT ALL THE HOSES FROM THE FUEL TANK.PLACE A LARGE FLOOR JACK CENTER OF THE FUEL TANK.PLACE A PIECE PLY WOOD OVER FLOOR JACK LIFTING SADDLE TO KEEP FROM PUTTING A HOLE IN FUEL TANK.START RAISING FLOOR JACK UNTIL SADDLE TOUCH GAS TANK JUST ENOUGH TO HOLD TANK IN PLACE.THEN YOU REMOVE FUEL PUMP SUPPORT STRAP BOLTS DROP FUEL TANK DISCONNECT FUEL SUPPLY AND RETURN HOSES AND DISCONNECT FUEL VAPOR LINES FROM PRESSURE RELIEF ROLLOVER VALVE.THEN REMOVE TANK.IF HAVE TROUBLE REMOVING FILLER TUBE AT GAS TANK SPRAY WD40 AROUND WHERE FILLER TUBE GOES TO GAS TANK LOOSEN THE CLAMPS AND USE LARGE VISE GRIPS WORK FILLER TUBE HOSE AWAY FROM FUEL TANK SPRAY WD40 INTO IT SLIDE ON OFF.WHEN YOU GET FUEL TANK OFF USE A FUEL PUMP MODULE LOCK RING TOOL TURN LOCK RING COUNTERCLOCK WISE.IF YOU DONT HAVE THE FUEL PUMP LOCK RING TOOL.YOU CAN USE A HAMMER AND BRASS DRIFT OR A PLASTIC DRIFT DONT USE NO METAL DRIFTS OR PUNCH YOU WILL MAKE A SPARK AND HAVE EXPLOSION FROM GAS FUMES BE EXTRA CAREFUL.REPLACE FUEL PUMP SOCK AND FUEL SUPPLY LINES IF STOPPED UP AND REPLACE FUEL FILTER.PUT EVERY THING BACK IN VISA VERSA.IF ALL GOES WELL. GO TO AUTO PARTS STORE BUY A GAS CAP WITH A LOCK SO WHO EVER PUT SUGAR IN YOUR GAS WONT BE ABLE TO TRY IT AGAIN GOOD LUCK.

there are gasoline vent tubes running on top the tank to the filler neck. check to see if the hoses are compromised in any way. these tubes also run to the front to a evap canister check these as well.

normally fumes come in to vehicle when stopped because of oil leak from rocker cover but check your fuel filler cap seal etc and also incase the tank is leaking just have a sniff at the rear of the car if its the filler cap or tank filler you normally get smell when tank is nearly full and been around a few corners the fuell filler nect becomes pourous and just spills out a bit if so will need replacing .but most time its an oil leak from rocker box or engine

It is a fuel pressure regulator. About a $60 item & 20 mintues to change.