What type of Clock is in a 1983 el camino and what are common problem?

It is probably just a 12V motorized clock. If so this type of clock is not known for accuracy.

Remove the back cover of the clock. If you see a bunch of gears, like on a wind up house clock, a couple of small squirts of WD-40 might get it going again. These types of automotive clocks are actually self winding movements. About every two minutes the clock winds down and a set of electric contacts come together. When they do the points arc and are forced apart, winding the clock again. Once you get it going it will probably run super fast. To correct this adjust the hands backwards to the correct time once a day. After about a week of doing this the clock will be regulated to keep good time. I repaired the clocks in my 66 Cadillac and 70 Pontiac this way. If the clock is a quartz movement you'll need to send it out to be repaired. You can also have a wind up movement converted to quartz for a nominal cost. One last thing about the wind up version. If it gains time, turn the hands backwards. If it loses time turn the hands forward. This will regulate the clock to run a little faster or slower as needed. Hope that helps! Jim