Today in the morning I tried to start my 1998 4cyl Accord but it had some difficulty on the first try it; was ok on the second go around. Later today it would not start at all, but would crank slowly to no avail.. I got a jump from my son and it started right up. My mechanic said it was the battery so I got a new one. My question is: I notice that the tachometer is all over the place in the 0 to 1000 range. Before this happened it would stay at 700-750 at idle. Is this occurring because the ECU is relearning my engine setup from the necessary sensors? I am not used to these sophisticated computerized cars, so please bear with me. Thanks