98 malibu

Wassup with everyone. I just purchased a used 98 malibu and the abs light as well as the check enginge light came on. Well I took it back to the dealer that I got it from and they said they "corrected the situation" but then I started to drive it and the check engine light came back on they said they ran a diagnostic test it cam back with nothing wrong and they changed the spark pulgs. I just need osme help with what might be wrong with my car.

First my abs light came on intermittently. Then the check engine light would occasionally appear. After a couple of weeks, the whole dash went crazy. A new alternator fixed my problem.