i cannot put gas into it other than barely trickling a penny at a time

Sound like the filler neck to the fuel tank is clogged or the EVAP canister outside the fuel tank is not working.

We purchase a used 1999 rx300 for our daughter and it had the same problem. Very frustrating! When I researched online, there were many costly and time consuming possible solutions. I wasn't about to try any of those just yet and continued searching for answers. Someone suggested cleaning contacts on the battery with water and baking soda to correct a gas gage problem I was also having. This sounded like something I could take on myself, so I tried it. I removed both connections to battery, cleaned battery with water and baking soda, dried off, rubbed a small amount of Vaseline on posts and connections then put back together. The next time I went to fill up, it pumped fine! No stopping! This fixed both problems my gas gage (was not register a full tank) and pump auto stop every few seconds while trying to fill tank. Have not had this problem in over 3 months.