I bought the Haynes version of the shop manual yesterday and quite frankly feel it was a waste of money. The basics it shows I can figure out, the hard stuff, like testing the sensors and what values they are supposed to have was useless. They gave values for some and not for others. Anyway, I am not great with an ohmeter but here is what I got from the EGR Valve, they actually supplied values for it. I got about 3600 ohms when no vacumn was applied to the valve and around 600 with 12hg of vacumn. The book said 5000 and 100 respectively. My actual reading at 20k were 3.57 and .61. My guess is the unit is faulty.

The codes I got from my computer were 34 and 41 (93 f150 5.0 aod). I checked the oxygen sensor and the heater wires returned 8.3 to 9 and heating the sensor produced the correct lean and rich values, within the 3 second time period. Could it be possible that the egr valve is causing the o2 sensor to act up? The truck does not run badly, in fact it runs well, its just every once in a while when I slow down to about 20mph sometimes the light comes on, or if I am driving in traffic stop and go, sometimes the light will come on, it usually turns off by itself.
Thanks in advance,

Regards,

Bryan