Business ProfileforMohawk Auto Sales

I'm a single grandmother 64 years old. I purchased a used car from a small dealer in North Adams. The vehicle is a 2011 Nissan Juke and I paid $6700 for it. At the time of purchase the dealer told me to come back if the vehicle didn't pass inspection. I had the vehicle inspected w/in the 7 day required time and it failed due to an engine misfire issue. The dealer took the vehicle back several times, each time returning it to me saying it was fixed but with the Check Engine light still showing. After the 60 days allowed by law to repair the vehicle I had no choice other than to try to have inspected again, it failed a second time for the same reason and code. I've since been told by a Nissan dealer there's a crack in the engine and it needs a new engine at a cost of $4,000. When I went back to the dealer he said he had no legal responsibility because the vehicle had over 125K miles (148k) The dealer at first stated he wanted to "work with me" by looking for a vehicle I could purchase & use the Nissan as a trade in but in it's current undrivable state the value has dropped to $2,000. I've spoken to the dealer once since this and it's now been months...when I check in with him he says he's still looking. This dealer has refused to take any further steps to rectify the situation so that I have a drivable vehicle. While I understand under MA Law there may be no legal responsibility on his part, I feel it's extremely unethical that he's taken my money, sold me an undriveable vehicle and has left me left me in this position. I have a vehicle I paid $6700 for plus cost of registration, title and sales tax totaling over $7,000 and I can't drive it.