What could be wrong?

Hi, I'm hoping someone can help me.
Yesterday my 1998 Kia Sportage was running just fine. Today when I tried to start it up it kept dying. If I keep my foot on the gas pedal, it will keep running, but as soon as I hit the brake it shuts down. The Hold light is flashing as well. According to the owner's manual, this is a transmission problem. I don't understand becuase it was running just fine. Could it have anything to do with the gas that I filled up with yesterday? Any help / advise would be great...thanks!

If the hold light is flashing then the check engine light must be on too.

An error was detected in the TCM (Transmission Control Unit). But that shouldn't cause the engine to stall so something else must be occuring too. Get the engine computer scanned for the trouble codes. It will provide important clues as to what is causing both problems. Any local Autozone will scan the computer for free. The trouble codes will be formatted PXXXX, where XXXX will be a series of numbers. There will be multiple codes stored. Get all the codes that scan out and post them here. We can provide items to check.