I just bought this car a few weeks ago, so I don't know much about it. The car is trying to stall out. The rpm's will drop low then jump back up and keep repeating the same pattern. This mostly happens when at a stop light/sign or even parked. I've started to notice that it does it while driving as well. While this takes place, I'll press on the gas and there seems to be a little bit of hesitation between me pressing the gas and the car responding, which usually ends with the car jolting forward. Even while driiving (under 25mph) and pressing the gas pedal the car seems to drop out as if I let off of the gas pedal. It'll only drop out for a split second but it's long enough to notice the drop.
I checked for codes and received,
P1599- Engine Stall or Near Stall Detected
P1189- Engine Oil Pressure Switch Fault
Just an FYI, I changed the oil and replaced the fuel filter. I do remember the previous owner mentioning replacing the front motor mounts and brakes. I had a few friends make recommendations, like the mass air flow sensor or tune up, etc...