Tony's Auto Sales Inc Lemon Cars that won't pass DEQ portland, Oregon

I went to Tony's Auto Sales in search of a new car. I opted to get a 1996 Mercedes Benz.  I traded in a 1978 Cadillac Deville showcar valued at $16,500.  Tony agreed to take the trade and offered me the Mercedes Benz. He requested in the trade that I give him $300 for paperwork and the 1978 Cadillac. I gave him a clean title and the Cadillac passed DEQ.  Tony told me that he had a clean title and that he would give me the title once I brought him the $300.  Once I did, he gave me lien papers.  I tried to take the car in DMV in WA to registar tne car as well as in OR, which they told me that I needed to take the car through DEQ.  I went to DEQ and the car failed DEQ.  I then called Tony back to see why he would sell me a car that would not pass DEQ, as well as no title.  Tony said he would take care of the problem and to bring him the car.  Once I took the car back to Tony he said that they fixed the problem and told me to pick it up and I need to drive the car for 40 miles and it would reset.  I drove the car 60 miles and then went back to DEQ, where it failed again.  Called Tony a second time and he and his mechanic told me to keep driving and it would reset.  So I drove the car 200 miles and then went to DEQ again and it failed.  Called Tony again and he said bring him the car in which I did so.  By this time I am out of a car, he keeps giving me the run around and saying it will be fixd tomorrow 4 weeks later.  By this time I have had enough of the run around, I told him to reverse the deal.  He said to let him try one more time and if it doesnt pass that he would reverse the deal and give me my 1978 cadillac and $300 back.  Tony has been laughing, making 3 way calls to his mechanic, which while the three of us where on the phone (Tony, myself, and DEQ Dan) Dan stated that he does not think it will ever pass DEQ and nobody can figure out what it wrong with the car.  At this point I am carless, because he still has my 1978 cadillac and cannot figure out what is wrong with the Mercedes.  I really do not trust him anymore or his mechanics to fix the car. I feel that they are at a point where they are trying to jimmy rig the car to pass DEQ.