Emailed back and forth with dealership and came to an agreed price through email only. No contract or money was exchanged but dealer removed the online ad for the car. If I decide I don't want it now do I have that right? Still no paperwork signed and no money exchanged. Only words through email.

Where? I'm not 100% positive that your email WASN'T a contract - if both parties agreed to the terms, both parties benefited (he sold the car, you bought the car) I think it could be interpreted as a contract.

The deal was through a dealership in TX

You did not make it entirely clear but is it safe to say you accepted his price or vice versa? If you made an offer and he accepted there may be more than a verbal contract. What does the dealer say, you have to tell him sometime.

The dealership has mailed the papers for me to sign, I haven't received them yet and was just tossing around the idea so I haven't mentioned it to them yet.

I do believe this could be construed as a verbal contract. You do have "wiggle room." Depending on the dollar amount I would consult with an Attorney.

The longer you wait before you advise the seller that you are no longer interested the more offers he can claim he lost on the car.

You might offer to pay his expenses (including the new ad) and try to get out of the deal that way.

I don't know how persistent he will be. As I said, if there was a verbal agreement to terms and you both stood to benefit from the "deal," you had a contract.