87' Accord, does not shut down after ignition is switched OFF, it keeps stalling. At this condition when i move the ignition to ON position the car starts without the aid of the starter. I had to get it off by switching the automatic gear randomly from P to D1 and back to shut the engine and switching OFF ignition. I observed while this happens the RPM goes to 3000 or little more than that and if you try driving at this condition, the car jumps as soon you put the stick to drive and accelerates automatically without pressing the gas. Would appreciate some help. Thanks in advance