Over last weekend, my car developed a problem with Speedometer gauge
and also the check engine light is coming on. We were driving to
another city and after driving for 350 miles or so, suddenly the
speedometer started going back and forth (even though the car was
running at a constant speed) and check engine light came on. Opening
the hood did not indicate any problem and since we were in the middle
of really small town on 25th Dec we kept driving for another 200 miles
before we found a good shop (the speedomter worked fine for speed less
than 60 miles (approx) at a constant speed but if we braked or speeded
it started going back and forth). Mechanic told us(based on
computerized testing) that the fuse blew up (7.5 amp fuse that keeps
track of alternator sensor and speedometer sensor). After replacing the
fuse, next day we drove 200 miles and fuse blew up again. We replaced
one mroe time and same thing happend after 15 miles with almost same
behavior (constant speed worked ok)

Seems like some kind of short circuit. Any idea how to proceed. All the
mechanics in and around austin are asking for $70 mininum to have a
look to figure out where the short is.
Thanks

SS