Selling a used car is often a challenging endeavor. Now, following the recent Volkswagen emissions testing scandal, many owners of used diesel vehicles are finding that no one wants to buy their used vehicles.

While prices for used, gas-powered VWs seems to be remaining stable, prices for vehicles with diesel engines have dropped precipitously, according to the San Francisco Chronicle. The average price for such VW models has dropped by more than 16 percent, or about $2,000 per car, according to the Kelley Blue Book.

The drastic price drop began after VW was exposed in September for rigging its diesel emissions testing. During the same period, the average price drop for used cars overall was just 6 percent, or about $600 per car.

The Kelley Blue Book used car selling website kbb.com has not yet been updated to reflect the price drop. An analyst for the company said they are taking a “wait and see approach,” instead of reacting to what he called an artificial market in the current pricing for used diesel vehicles.

The auto industry research and analysis firm Edmunds also surveyed diesel prices since the scandal broke. They found an 8.6 percent drop in prices for VW diesels following the September 18 announcement of the emissions test rigging.

Edmunds also noted that a seasonal downward fluctuation would be expected at this time, so the decline in prices may not be related to the emissions scandal. They continue to advise owners of diesel VWs to hold onto the cars until the company comes out with a definitive fix or buy-back proposal.

VW dealers can take the used diesel cars as trade-ins and they can re-sell them, but they are not allowed to market them as “certified” used cars. They are also prohibited from selling any new diesels that have been subject to the recalls.