I'm curious why you're playing with the solenoids, what's the problem you're trying to solve? The evap system self tests won't try to run if the fuel level is above 85% or below 15% If your fuel sending unit is bad and the tank doesn't have an accurate idea of how much fuel is in the tank - it could be causing your problem? (I'm assuming check engine light and a code or two).

 

code po440 evap code.probable cause.defective or loose gas cap..evap canister or hose crack or not connected..purge or vent solenoid defected..vacum leak at engine..that what i was wondering keep tank always full so evap test dosnt test.

 

my check engine light is off.been a week now.it was comming on every 60 to 70 miles after unscrewing hot wire at fuse box under hood.a week and no light so far.i bought new vent solenoid at chevy dearler 25 bucks and no light yet.thank you blazer forum for all the help

 

well it has been 3 weeks from when i put the new vent solenoid on and still no check engine light.i believe the problum was solved.thank you blazer forum.

 

did you have to put a new hose on it?