I am having a problem with my motor backing down to 4400rpm's. It will get to 5600 when I first take off for the first time but backs down after about two minutes. I have checked the fuel pumps for leaking diaphrams and they were ok. One of them had one of the check plates loose but it didn't solve my problem when I fixed it. Could it be the O2 sensor or is it still a fuel problem. I also changed the fuel filter element.
