I have a 2003 4.4L with similar issues. My speedometer works 9 out of 10 times we use the car, but 1 in 10 there is no speedometer, ABS light and traction control warning lights are all on. Think this is the sensor going bad even though it's not 100% of the time, or does that sound more like a failing computer or something else entirely? One other interesting detail is that when i hookup the ODB2 reader it picks up the correct speed in the monitor mode. Thanks for the help!