Ok, this is what happens. Sometimes when I try to pump gas into my '99 V6 camaro, the gas spews back out and I have to use a wire hanger to get rid of an air pocket. What could be causing this? It was around 4 months ago the engine was replaced and this has been happening ever since then.

 

Do you have the rubber boots on the gas pump nozzles? Try pulling back on it or pull it to the side so you can see it does not seal on the filler neck. Or even turn the pump handle so its upside down with the hose pointing up.
Also check your evap lines like to the canister. Maybe the vent line got pinched.