I have an 88 Bronco XLT 4x4 with a 351W. It has been idling rough so my buddy ran a diagnostic on the computer and it returned a code 84. I have been trying to figure out what exactly I need to check for the EGR vacuum regulator circuit. Unfortunately he has left to Iraq before we could deal with this issue more. I have checked for vacuum at the EGR valve and there is none even when I accelerate to high RPM's. I traced the vacuum line back to the EVR and pulled the vacuum lines.......with engine running and accelerated there was no vacuum from either points. I am at a loss at this point. I have pulled voltages off the EGR Valve position sensor and (as if looking at a triangle) the top wire returned a .21V, the left wire returned 0V and I believe the right wire returned a 5V. I also pulled voltages from the EVR and both pins with just the key on was 1.36V and with engine running it was at .5V. I have no clue what else to check at this point. The engine idles rough and is sluggish when I floor it at take off.