Looking to buy 94 LeSabre Custom but......

[tmacke]

104000 miles, elderly driven, looks in real good shape.
Took for test drive, after about 5 miles I was getting off the freeway when the service engine soon light came on. Upon return, shut off & restarted engine and light stayed off. Son in law of owner drove it a couple of days later and had same thing happen. I know I need to take it where a computer can read the codes but does anyone have common reasons I can expect and how costly are the repairs.
More importantly, the oil pressure gauge stayed around 30 at higway speed and dropped a little at stop signs. Is 30 an ok reading?

Any input greatly appreciated to a newbie of this site.

[johnd89]

whenever you buy a used car is a good idea to invest some 50$ and go to a garage and have it inspected. if they discover something the owner didn't told you before, you have a good base for bargaining.