We just bought a 93 honda accord that appeared to be in good shape...appeared being the key word. We even had a mechanic check it out...anyway the tach doesn't work. When the car starts it goes up to about 2000 and just stays there. Every once in awhile it will jump and read what we think it correctly for a few miles, then it drops again and stays right there. We can't find anything about the tach in the chiltons manual? Can you help us figure out what's wrong?

Optional Information:
1993 Honda Accord

Already Tried:
Nothing...can't find what we're looking for