We just replaced the throttle body on an 02 honda civic and now it shifts into neutral before advancing to the next gear. It's an automatic. Before we replaced the throttle body, the check engine like would come on, and it would race and not shift. If we put it in neutral and shut it off while coasting and start it up, it would correct the problem so we replaced the throttle body as the code indicated to do but now it doesn't shift properly. Can anyone help?

Sounds like a straight transmission problem, to me. If you haven't been changing the transmission fluid regularly (every 24 months or 30,000 miles), the ATX may need rebuilding/replacing. Before doing anything else, I would change the fluid and see if that helps:

https://www.askmehelpdesk.com/cars-t...ml#post2634481

Why would you be changing a throttle body for gear shifting problem? Normally TPS throttle position sensor tells the ECM on how much degree the throttle plate is moved and accordingly the ECM commands the shifting. The problem here is that the TPS has to be adjusted and you would need a scanner to do this adjustment.