1991 Sho

Just purchased the car, the check engine light is on and i dont know why any ideas how to fix without spending $2000 at a mechanic

Find out what the codes are.
http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/0c/e2/3b/0900823d800ce23b.jsp

what if i dont have a code reader where could i go to get them read :uhoh:

Did you look at the link I provided?
Try Autozone

http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/0b/fd/a5/0900823d800bfda5.jsp
USING THE MALFUNCTION INDICATOR LIGHT (MIL)

Read the whole section "Self-diagnostic Systems"

You can pull the OBD-I codes yourself using just a jumper wire.

Scroll to the bottom of the page at the following link for details:
http://autorepair.about.com/library/ts/obd-i/bl-dtcs-98.htm

The EEC and self test plugs on your '91 SHO will either be hanging near one of the strut towers or possibly installed in some connector covers at the firewall on the passenger side (in US).

-Rod
-Rod