My speedometer on my 1995 Honda Accord doesn't

First thing to do is have the computer checked for trouble codes. The blinking D4 light means overdrive is not going to function, probably because of the rough running engine.

is the speedo connected ??

Vehicle speed sensor. Top of the tranny is a connection. From this, a cable runs to the back of the odometer. Probably need to replace it

Usually it means the speed sensor in the transmission is failing.
The blinking light means your overdrive may not work.

I had the same problem with my 95 accord, your vehicle speed sensor is going bad, the part new is like 100 bucks, you could possibly find one at a junkyard, I had to buy one new, the sensor itself will sit on the passenger side, under the intake hose, its a pain to get to if you have large hands. But it is something that you definitely need replaced

engine check light does come on if your VSS doesn't work.
i suggest you use a car diagnostic tool check your car.
mvci honda toyota have a look.

two things speed sensor, or odometer cable very easy to repair, try sensor first , have someone test it for you with a on meter,

watch out for tranny & sensors get it checked out asap

When the D4 light flashes that is an indication of a problem with the transmission. You need a speed sensor located on the transmission make sure to get the electrical part ths will solve BOTH problems.

Check the honda accord forum. I think there are many posts on there about a blinking D4 light