Once a transmission starts slipping, it's time for a rebuild. Sorry. Drive it as is till you save enough money for a rebuild or used transmission.
But a shot in the dark, you can also check to see if the TV cable is hooked up. There is cable with a spring that attached to the underside of the throttle body next the accelerator cable. Most times the plastic grommet cracks and the cable is not attached. You can buy a new one at your local auto parts store in the HELP section.
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