Check Engine Light on 1998 Cadillac Seville STS

I had the EGR valve replaces on my car back in November, the check engine light went compeletly off. Now the light is back on again. Is there a reasonable trustworthy Cadillac mechanic other than Cadillac Jaguar of Northlake. I am truly looking and I know there is one out there.

Asked by for the 1998 Cadillac Seville STS