95 buick riviera running hot and backfiring?

[chrissy]

Just bought the car a lil over a month ago. When we first went to look at it it would not crank so we went and got gas and it cranked right up. The next day as we were driving down the road and it kept dieing but after about twenty minutes it quit that, That weekend my boyfriend changed spark plugs, spark plug wires, fan belt, and fuel filter. The car ran great for the next few days with no problems (except being really loud but that was because the catalytic converter had a HUGE hole in it but we got that fixed also a few days ago). Then one day we were trying to make it a lil futher in the car and we made it about forty miles away from home and it started backfiring sputtering and dieing. It did that all the way home. I was then told it was the mass air flow sensor so I changed that which helped with the idling sometimes but it still backfires and goes dead and sometimes just goes dead without backfiring. And now to make matters worse it started running hot and I don't know what to check or how to check the things associated with that except for changing the thermostat which I have done and it does no good. Please help any advice would be appreciated.