1991 Lexus LS 400 Transmission

One day I was driving and all of sudden it was like my car was in neutral it did not wanna go. Before this my car would shut off right after I start the car every once in awhile so I changed the o2 sensor, the TPS sensor transmission fluid and filter. Now when I put my car in drive I have to hold down the gas for a while to get it to move then it drives fine and it goes in reverse no problems. Everyone tells me that there's a lot of sensors I don't know which ones to replace.