Where is the canister vent solenoid on a 1998 Chevy calivier?

This depends on the actual date manufactured. Most likely under the car next to the fuel tank in the ventialation canister. If you have a code set in the ECM on this solenoid then it was most likely set because when a person pumped gas into the car they tried squeezing that last little bit into the tank and this is a huge NO NO. When this is done it saturates the canister with gas and can cause alot of problems. Basicaly the cheapest way to correct a fuel canister problem is to keep using the car and after all the fuel has evaporated out of the canister the problem will go away. Remember when pumping gas to only pull the triger on the pump half way and take another minute longer to prevent this plus the first time the pump kicks off then it's full. Don't try squeezing that last few since in. Doing this will keep any problems from occurring in the Fuel Ventialation Canister.