if the check engine like is just cycling on and off it is most likely a O2 sensor. For the 95 there are instructions in the faq on how to get the code, do that and post them to find out what to do
the speedo is most likely linked to the VSS, there shouldn't be any reson for the sensor to fail, check that the connection is clean and that the cable isn't pulling on the sensor, also you can spray some silicon on it to help out, you will not have a speedo cable unless your car was built before feb 95, if it was then it is going to be the speedo cable
