1994 VOLVO 940 Engine And Engine Coolingexhaust System Problems

I WAS SOLD A VOLVO 1994 940 SERIES FROM EAST LAKE AUTO IN ISSAQUAH, WA. A CHECK ENGINE LIGHT WAS DISPLAYED AND THE COMPANY PROMISED TO FIX WHATEVER IT WAS INDICATING. I LEFT IT AT THEIR SHOP FOR INSPECTION, AND WAS TOLD THAT THERE WAS NO PROBLEM RELATED TO THE LIGHT, AND THAT IT WAS A FAULTY LIGHT. I DROVE THE CAR FOR THREE YEARS WITH THE CHECK ENGINE LIGHT ALWAYS ON. I COMMUTED TO A JOB THAT REQUIRED I BE IN THE CAR FOR OVER THREE HOURS ON MOST DAYS. I MADE A LONG TRIP AND AFTER THAT MY SONS AND I HAVE HAD MANY NEUROLOGICAL PROBLEMS. THE COMPANY WAS CLOSED DOWN ABOUT SIX MONTHS AGO. DUE TO ANOTHER TYPE OF REPAIR, I TOOK THE CAR IN TO ANOTHER MECHANIC TO BE TESTED FOR A BROKEN WATER PUMP. THE NEW COMPANY TOLD ME THAT THE CHECK ENGINE LIGHT WAS...