Will a faulty vacuum bypass valve cause my truck to misfire badly, to the point of shutoff?

Question

2001 Nissan X-Terra. 145000 miles. Drove perfectly until the other day when out of the blue, the vehicle began missing. So badly that it wants to shut off...

Answer 1

The vacuum bypass valve , is installed parallel to the purge valve, if the solenoid is stuck in the open  position this would cause vacuum in the tank. You would have a higher than normal idle, If the engine is misfire badly, the misfire cause has to be identified . a stuck open or closed vacuum bypass valve will not cause a misfire condition to  of wanting to shut off.