1998 Toyota Camry sometimes speedometer at zero, not always smooth. on 1998 Toyota Camry

My Camry has over 186,000 miles. Over the last year or so,I have had problems with the speedometer going to zero and odometer going blank. The speed sensor and instrument panel have been replaced.I notice when I turn in certain places the odometer goes blank. Sometimes when I brake this happens too. The SS goes off by itself and comes on by itself. It used to come back on when I drove on the highway where the road goes uphil, but I haven't been doing a lot of that driving for a couple months.Lately, its been showing zero before I even start the car. When the speedometer goes to zero the car gives a little push like when you go into cruise control. Sometimes when I brake it drives stiffly as thought it doesn't want to go. A couple times I just had to pull over and wait a while then start driving again. Lately this problem has been happening every day a several times a day. The speed sensor and instrument panel have been replaced, but things only improve for a short while. I would like to know what is the ROOT of the problem.

Asked by for the 1998 Toyota Camry