Hello. I have a question about my blacktop. ever since I have had it, its had a flat spot. Mainly if push the accelerator 3/4 of the way and hold it, it sounds like its running on 3 cylinders (flatspot) then u push it to the floor and its fine. It only when you hold it at quarter throttle. Now I have pretty lame spark plugs $5.00 ea and I think its ment to have platinums. teh Oxy sensor is a 4 wire sensor from coventries and FORD make it. I asume the sensor has been wired up correctly as it has not problem with reving at high RPM. I also get 350km out of a tank and 400 if I am lucky, I am not sure if that is normal but any details will help I guess. Any ideas of what my problem may be is much appreciated