* Vapor Recovery System (VRS): This is the most likely reason. Older vehicles, especially those from 1999, often have less sophisticated vapor recovery systems. The pump will stop periodically to allow the system to "catch its breath" and prevent gasoline vapors from escaping into the atmosphere. This is a regulatory requirement designed to reduce air pollution.
* Pump's Internal Safety Mechanisms: Some pumps have built-in timers or flow rate limits as a safety precaution. This prevents accidental overfilling or other issues. The five-second pause might be a programmed interval within this safety mechanism.
* Fuel Tank's Design/Pressure: The shape and venting of your van's fuel tank might be contributing to the issue. If the tank is difficult to fill quickly due to its design or venting system, the pump may pause to prevent pressure build-up within the tank.
* Faulty Pump or Nozzle: While less likely, a malfunctioning pump or nozzle could also be the cause. A problem with the flow sensor or a partially clogged nozzle could lead to intermittent stops. Try a different pump at a different station to rule this out.
To troubleshoot:
1. Try a different gas station: This helps determine if it's a pump-specific problem.
2. Check your owner's manual: See if there's any information about fuel tank filling peculiarities for your van model.
3. Observe the pump closely: Note if any error codes or messages appear on the pump display during the pauses.
4. If the problem persists: Consult a mechanic who can inspect your vehicle's fuel system and check for any potential issues.
It's less likely that the problem is specifically *with* your 1999 van itself, but rather an interaction between the van's fuel system and a safety feature or limitation of the gas pump.
