Thanks for the additional information. She likely does have motion sickness and the one time she had the experience of a drive, she got sick which reinforced her belief that the car is a bad place. So besides needed to get her into the car, you also have to stop her getting car sick. So let me give you information on car sickness first and then we will attempt to find a solution to getting her into the car.
Motion sickness is worse if you can't see out a window so sometimes allowing a dog to be in the front seat in a harness will help. Some people use Benadryl to calm their dog before car travel and Dramamine is also used for motion sickness, but your Vet should be consulted before using Dramamine.
Benadryl can be given to your dog, the dose is up to 2mg per pound every 8 hours. The dosage for Dramamine (Dimenhydrinate) for motion sickness is 2-4 mg/pound by mouth every 8 hours. Dramamine works best for my own animals.
Any medication should be given an hour in advance to car trip. For anxiety, herbal rescue remedy is often used, but another option is a DAP collar that uses pheromones to calm a dog. It emits pheromones similar to those produced by a mother when nursing pups.
Next is getting her used to the car and I am going to suggest some obedience training to get her more used to always obeying you the first time you give a command and every time. The following site is helpful in helping owners train their dog. Be sure and click on the link to the page on obedience at the bottom. and links on subsequent pages leading to detailed instructions.
Training works best if you train at least 30 minutes a day (two 15 minute sessions). I would start making your dog work via the Nothing in life is free program (NILF). It is outlined below.
The next step will be getting a long leash and attach it to the car and start feeding her outside . Start at the outer reaches of the leash and daily move the food closer and closer to the car until it is right next to the car. Leave it next to the car for at least a week. Then open the door and put the food on the floor in the car for a week or so. The next step is putting it inside the car. You can be outside but don't be near the car for this step. Once she is eating inside the car and it may take a day or two for her to do that, then close the door but open it as soon as she is done eating. After a couple of weeks of this, you can then close the door and start the car but don't move it. After a week of this, start giving her the medication an hour before hand and moving the car a few feet before stopping and putting the car back. Gradually lengthen how far you move the car. By now she shouldn't be getting car sick and it should be more enjoyable. You might switch to a high value treat instead of food at this point like hot dog slivers.
It is a long process but has the highest chance of success when done in this manner.
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Since there have been recalls on certain foods, please check the following site to be sure the food your animals eat is not affected. If it is affected, contact your vet as soon as possible. Have your dog seen if they have any symptoms.