Do nitrous solenoids go bad?
 

Just wondering how you know if one of your solenoids go bad? Is there a way to find out before spraying? Also if they start to go bad...will they gradually go bad or will they just one day work and the next day wont?

Nitrous solenoids are generally high quality. While I'm sure they do go out, I've never seen one. You can test them with a paperclip. When the magnet energizes, the paperclip will be attracted to the solenoid. You will also hear a thunk.

You can tell if the nitrous solenoid is working by listening for the woosh while shooting. If you turn off the Nitrous, then shoot nitrous, the car will bog slightly from the extra fuel.

When you buy a new tank, if you heat it up to about 1200-1300PSI with a bottle heater, the nitrous solenoid will not open. You can also test fuel using this method by listening for the thunk.

Yes, they go bad. This is why when I build a car at the shop, I use two fuel solenoids in parallel and two nitrous solenoids in series.