91 honda accord

lately my speedometer jumps up and down when i am driving and the other night my s light started blinking, also my shifting sucks, no gears slip but i think its my ecu or my transmission control computer i need to know which one it is please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

You have an "s" light? what is that?
Have you tried to check the speedo cable? Or do you have a electronic speedo?

VSS vehicle speed sensor, do a search. TCM doesn't affect your speedo...I bet your cruise control doesn't work right either...correct? Do a search for vss or speed sensor and you'll get your answer. I have a 90 accord, that I'm parting out...if you wait until thanksgiving, I'll sell you my speed sensor for $50

whtteq - the "S" light was a brief and abortive excursion by Honda into trying to create a car that was either "basic" or "sporty" by having a "Sport Shift" button on the shifter. It was a frost. They stopped it in a hurry.

And, by the way, I suspect ALL Hondas have had eletronic speedos since about 1914.

(But, as noted, it also served as a warning light).

Accord did not until 90 come to find out. I know that my friends 88 accord had a speedo cable b/c I changed his clutch for him ;)