So, my focus ran fine for what it is(SPI) this morning. Then I went to start it leaving a store and got a loud squeal and hesitation, so I cut it off and restarted it and it ran fine all the way home. Then tonight when I went to get in it, it starts but makes a grinding noise, sounds like it's gasping for life and the exhaust makes popping noises. It will move but accelerates/idles like crap and only will hit very low rpms even on the gas. I have no idea what's wrong and replacing the engine isn't an option in my book. Im hoping this isn't an engine problem because that would be the end of the car, therefore the end of me buying fords(sorry I sound harsh but I have to go to school in the morning and can't make it by any means). Someone please help!