I have a 1997 Plymouth Grand Voyager with 171000 miles on it I keep getting the code p1698 how do I fix it
That's a communication failure between the engine controller and transmission controller. Could be a bad ground or something more serious. (Sometimes Jeeps of the same vintage will develop that fault.) Here's a link to an explanation of the problem, and a simple fix on a Jeep that was successful, you may get lucky and find something similar. (You always want to start with the simple stuff first.)
https://www.fixya.com/cars/t3233600-check_engine_light_code_p1698
https://www.jeepforum.com/forum/f11/p1698-no-bus-message-transmission-control-module-1359085/
It comes and goes then it comes back on and it goes off for a while I have changed the tcm
Sounds like you may have a wiring or grounding problem as described in the links. I'd look into that before replacing any other components.
Sounds like an electrical fault. Could be a real pain to track down honestly.
Could it be the instrument cluster they are known for having problems