Toyota Repair: 1987 Cressida fuel gauge & speedometer., gauge speedometer, circuit failure

Question
I bought a 87 cressida for my daughter. It has 82,000 miles. It is in very good condition bought from orig. owner. The fuel gauge works sometimes but for the most part reads "empty". Is it possible that this might just be a bad connection on the sending unit? The speedometer reads high most of the time ( 90 when doing 25)but sometimes it registers properly. Does this have a cable or is it electronically read? How can I diagnose if it is a bad speeometer head?
Thanks

Answer
Some of these had an analog or digital dash, which one does this car have?
I'm thinking that there is a problem with the printed circuit bord on the back of the instrument cluster, I'm pretty sure it has a speedo cable but the signal is converted from an analog to an electronic signal in the speedo, since there are these two problems I still think it's caused by a circuit failure in the instrument cluster.