I have a 2000 tahoe with a 5.7 litre. On a long drive the engine light came on. When I continued to drive, it had a sound like the A/C kept drawing power from the engine but this was only intermittent and barely noticeable. The following day it started with trouble and then the next day it would not start; battery power is strong. Diagnosing the code from the digital reader comes up with a code P0440 which is a generic emmissions number. Any ideas where to go from here?

A code P0440 could mean one or more of the following has happened:

• The gas cap is not installed or working properly
• The purge solenoid has failed
• The canister is plugged and not working properly

• 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

I would check out the smog pump,it is most likely ting to lock up.About 118.00 at N A P A