P0440 Code

[sc89]

Hey guys, I wanted to know if anyone can give me a hand with a check engine light code, P0440, Emissions Evaporation System. I get 15mpg going 55mph, but used to get 18-19mpg going 72mph (the trucks runs m1 synthetic oil and filter, new spark plugs, spark plug wires, o2 sensors, battery, etc). I am not sure where to begin on how to diagnose this problem, any substantial help would be appreciated..thanks in advance

[vanuatoo]

Hey guys, I wanted to know if anyone can give me a hand with a check engine light code, P0440, Emissions Evaporation System. I get 15mpg going 55mph, but used to get 18-19mpg going 72mph (the trucks runs m1 synthetic oil and filter, new spark plugs, spark plug wires, o2 sensors, battery, etc). I am not sure where to begin on how to diagnose this problem, any substantial help would be appreciated..thanks in advance

 

http://www.obd-codes.com/p0440

 

With a P0440 OBD-II trouble code, diagnosis can be tricky at times. Here are some things to try:

 

* Remove and reinstall the gas cap, clear the code, and drive for a day and see if the codes come back.

* Inspect the EVAP system for cuts/holes in tubes/hoses

* Inspect for damaged or disconnected hoses around the Evap purge solenoid

* Check and/or replace the sensor

* Check and/or replace the purge valve

* Have a professional use a smoke machine to detect leaks