98 Honda Accord

Engine stalls, push on the gas pedal and engine misses or******, non responsive - this is not consistently happening - I've changed plugs and wires, oil and filters - just purchased this car from its one owner - they had this trouble all along - they believed it was egr valve - I changed that too, it still has problem - I'll come to stop, then when push on gas, it has no or a delayed response -when idling sometimes its ok, other times it starts missing and sometimes stalls