I've been working on getting a '94 DX running that I bought. The first time I drove it the speedo quit then after a while it started jumping all over the place and then sometimes it would work. I got a new speed sensor and put it on but still does the same thing. Tonight I reset the trip odometer and when I pushed the button the speedo went to 100mph for a second...I was parked. So I'm pretty sure my speedometer is shot. My car is an auto and I DO NOT have a tach now. All of the speedos on eBay currently have a tach. Will these speedos interchange? If I put in a speedo with a tach, will the tach work? I'm not sure if the wiring and everything is already there or not.

Thanks,

Derek