Ever dealt with a customer who thought you were ripping them off? Or one that thought you could afford to pay a little more for a trade-in? Chances are they may have been wrong.

According to a new survey commissioned by TrueCar, car shoppers think dealers make about five times more profit on the sale of new car than they actually do.

The company released this week the results of its annual “TrueCar Buyer Study,” which focuses on the “trust gap” between consumers and dealers.

That is, when buyers fear they are overpaying for a new vehicle.

In reality, dealers new-car profit margins are shrinking.

According to the survey, shoppers believe dealers make about 20 percent profit on the sale of a $30,000 new car.

The truth of the matter: Dealer new-car profit margins are down from 5.5 percent in 2003 to 3.8 percent in 2013, according to NADA data.

Interestingly, this is much less than consumers think would be “fair.”

According to the survey, shoppers believe that a “fair” profit margin on a new-car sale would range from 10 to 12 percent.

Furthermore, if told that dealers theoretically made zero-percent profit on new-car transactions, consumers surveyed responded that they would be willing to "tip" them 8 percent on a sale — considerably more than the current profit margin.

Even though shoppers implied dealers should be making more profit off new cars than they currently are, 26 percent of survey respondents still said they thought they overpaid for their purchase.

The survey was conducted in February and surveyed more than 3,000 consumers in the U.S.