i took my truck into the Shop a few months ago to get the Fuel Pump replaced..When i got my truck back,,it had the Engine Service Light on..They ran it through Diagnostics and said that it was the Evap...They reset the computer and a week later the light came back on..I have noticed since then that my truck is not running right..what can be wrong with getting the Evap Code from getting my Fuel Pump replaced..

 

just to make it more clear..there was nothing wrong with the evap before i had to get the fuel pump replaced..after i got the fuel pump replaced...the code comes on and truck is not running right

2004 Ford F150 4x4 FX4....5.4l engine

 

More than likely they damaged a vent hose going to the EVAP canister.
The hose at #4 or #6?

 

i will try and take a look at them today to see if i can spot anything wrong with them..

 

The majority of the hoses and fittings are on the top of the fuel tank. You probably won't be able to see anything due to lack of access.

Which specific fault code are your getting? There are at least a dozen of them possible relating to the evap system. If it's one of the leak codes, a smoke test will be invaluable in finding it.

Steve

 

Something that they may not have discovered could be the fuel tank hose may have broken. I had discovered that mine had broken in place; which allows air to enter the tank.
My hose is rubber and had cracked at the clamps. The deterioration had left it still in place, but a line crack had started around the clamp. The EVAP system essentially wants to "see" a closed tank. If the vacuum doesn't drop the tank pressure enough the Fuel Tank Pressure Sensor reads "low" which can be interpreted as a EVAP leak.
There are many reasons for the EVAP CEL, but this problem is not usually discussed in the forums.