Shakes or Wobbles problem
1998 Mercury Sable 6 cyl Front Wheel Drive Automatic 104000 miles
My car, starts up fine. When it sits in park, is in drive but stopped or is driving very slow, the rpms drop to about 500 then stalls out. I need to hold the gas down(in neutral) slightly when im at lights or it stalls, when it is under 1000 rpms, the car jerks or sputters. When I drive sometimes I dont even need to press the gas, the car runs at higher rpms and gives itself enough gas to drive at 30-40 mph. When im on the highway the car speeds itself up occasionally and find myself doing 75 instead of 65, it speeds up the slows back down. I have no idea what is causing this problem and just last week spent all my money fixing other problems with the car.(Brakes, rotors and a ball joint.) Please help me figure out what the problem is!