I need someone who knows a little bit about Accord speed sensors...

I've got a 98 accord ex 4 door with the F23A1 4 cyl, automatic.

Symptoms:
Speedometer consistently too high-at 30 on the speedometer I'm going 26-27, at 70 on the speedometer I'm going 61-62, etc. So it gets worse the faster I go.

It will occasionally shift oddly, for example when I slow down it will occasionally downshift too soon.

When I'm trying to speed up and I kick it, it will downshift but make no power, after 3 or 4 seconds it will "kick in" and take off.

When idling, it gets rough occasionally. The more electrical stuff-lights, blower motor, etc. the worse it gets.

It runs great overall, shifts smoothly, no slippage, it's not internal transmission. For the speedometer, the occasional weird shift, and the lack of power for a second until it gets a signal, I'm thinking it's a speed sensor. But which one? There's one on top-it's black, has a bolt hole on the side, is 2 prong. There's one on the bottom, exactly the same. Is there a third?

I pulled them out, cleaned them off, no change. I ran the car with the one on top unplugged-No speedometer signal at all, wouldn't shift out of first, but the check engine light didn't come on. I ran it with the bottom one unplugged, shifted harder, no effect on the speedometer, check engine light came on almost immediately.

Any thoughts? Anywhere else I should look?

 

If other electrical devices are affected then most likely there is a problem with the electrical system.
Verify the battery is fully charged.
Make sure the terminal connections at the battery are clean and tight.
Check all your grounds are intact between the engine and the body.

 

Nah it doesn't affect other electrical systems.

I've also ruled it out multiple times, that was my first suspicion. I've got an Optima battery that's 6 months old, brand new terminals with plenty of dielectric grease, all grounds are intact, clean, greased, and retightened, etc. have 15+ volts all the time, alternator is pushing a solid 14.7.

 

I changed out the original tranny with a Japanese import. Any idea if that alone is the reason? What's different between the American version and the Japanese? Everything plugged in just fine aside from those two sensors which I pulled off my old tranny.