Speed sensor is sensor that generates a signal based on the transmission RPM. Some transmissions have 2 sensors.

A bad sensor can cause shift and lockup issues. The sensor also works with the speedometer and cruise control, and issues may show up here. A bad sensor can turn on the check engine light.

 

Is the speed sensor inside the transmission? I kind of thought you could access it from the outside?
I did the MAF in the Venza and I did notice a change in the shifting around town and rural driving. Just got the Camry back. They did spark plugs and cleaned the MAF on that also. Tomorrow I'll be doing a 100 mile round trip in a highway where I can set the curies at 70 mph and see what happens.

 

The sensors install and bolt to the transmission from the outside.

 

Did a 100 mile run with Camry today. The spark plugs and cleaning the MAF helped it a bit. Gas milage is still not normal. Cruise set at 73mph. It did shift into 4th gear a few times going up a grade which is expected. But it did downshift to 4th gear twice on level road. So I don't know what is wrong. This happened in a 2 week span.

 

What did the mechanic say?

 

He told me that should take care of it. They couldn't drive it in an area where they could test it out. I'll call again but I'm sure they will not know what to do now. They thought it had a CVT transmission and that they tend to rev like that. But I told him it was a 6 speed.