1995 Plymouth Neon high line review from North America

When I purchased this car it ran great, after having it for a year it started leaking oil and I was putting in 2 quarts a day, took it to the garage and they replaced a seal, then car ran fine for another year with no problems, then I had to have the starter replaced, then it ran good again, up till now, it is running very sluggish and it is starting to get loud and has no power to climb a hill, you have to put the pedal all the way to the floor to climb a hill then it starts making a noise that sounds like something is flapping, we just replaced the spark plugs and spark plug wires, gave it an oil change, well that's not the problem, can you please tell me what the problem could be?

The car ran great when it was running properly, really handles the curves nice, had no problems with rust, or water leaking in trunk or windows, I would certainly think about purchasing another neon.