2000 GMC JIMMY 4.3L ENGINE CODE P0440

” CODE P0440 INTERMETENTLY SHOWING UP. I KNOW THAT IS ABOUT THE EVAPORATIVE EMISSION SYSTEM. WHAT WILL BE YOUR SUGGESTION, TO FIND THE CAUSE OF THIS CODE? MY CAR IS 2000 GMC JIMMY 4.3L ENGINE. SMOKE TEST IS SO EXPENSIVE. Any cheaper way in mind? “

P0440 is the code for evap malfunction. The possible causes are bad evap hose connections, a leak in the intake system, or a bad evap cannister purge valve. The only way to really check it out is with a smoke machine, but you could try putting two or three pounds pressure into evap hoses and then spraying dishwasher liquid mixed with water on all the connections to see if they bubble up (you can’t use much pressure or you can damage the evap system.) If you can’t find any leaks, the cannister purge valves do go bad quite often on those 4.3 Jimmys. It’s just a guess without checking the whole system out, but if you can’t find anyone willing to smoke check the system at a reasonable cost, a guess may be your next option.