My Rodeo 96 has a P0440 code (Evaporative Emissions Control System problem). I have visually inspected the hoses on the engine; double-checked the gas cap is tight; but have not looked at the fuel tank sensors and connections. I've noticed that the EVAP canister purge valve solenoid is switching non-stop (click-click-click noise without stopping). Is it the expected behavior?
I have seen many of the Rodeo's purge valves malfunction causing rough idle and that clicking coming from the valve. It is not normal behavior for that purge valve. Double check all hoses for any hair line cracks, they tend to crack on the bottom side alot. Otherwise replace the purge valve it make a huge differnce in the vehicles idle and performance. Also a intake cleaning service helps quite a bit too, most lube centers and shops can do it for about 50-60$. That cleans all the carbon out of your intake plenum, port runners, valves. It may help the valve to stop malfunctioning also, have seen that service clear all codes and bring back lost power and rough idles clear up.
