Whenever I put new gas in the car, it has a hard time starting. The engine has to stutter for a while before it starts. Also sometimes the engine will rev up and down for a while before it runs normal.
Hello. It sounds like you may have a bad vent or purge valve in the evaporative emissions system. Most of the time this is caused by the purge valve. These valves work to contain the gas fumes in the vehicle until they can be burnt off in the engine at the correct times. If the purge valve is stuck open then these fumes will enter the engine while your are fueling. That will essentially cause the engine to run very rich right after fueling, causing it to run like this. A mechanic would typically remove the valve and check its operation or perform a smoke test.