I'm riiiich biaatch

so after a week of loving my car i'm verry concerned for it. the day i bought we realized that the car was running rich, i thought it could just be the bad gas the car had from sitting around for months. so we drove it around my neighboorhood 'till we got the gas guage low then we put in about a half a tank of gas in it it was ok. so today i just turn on my car just to sit in it and pretend to drive (because i don't have my license). so i turn on the car and a wierd screeching comes from the car, so i think it might just be my gas pump feeding the car to much. so i put the a/c on because it's a hot day i rev it up just to 1.5 and then the idle drops all the way down to 2-5 rpm and the car starts to rumble. then a violent screech comes from the engine kinda like if the fan belt was dry it comes and goes. then i open my hood and the engin is having a small seizure but it comes and goes. i'm verry concerned. i do plan on getting the engin rebuilt in september but until then what do you guys think could be the problem i might make a video of my issues later today.
the car has 225699kms on the clock