Dazed and Confused
Join Date: May 2012
Location: Upstate New York
Re: 1999 Navigator EGR issue, really unexplainable.
Okie doke, suggestion still applies, follow the EGR to the solenoid that sends its vacuum signal to the EGR and unplug it, see f it acts like you've unplugged the EGR, if not, it's either leaking or stuck open. If it doesn't and the PCM is correct, then you might have a short in the signal wire to the solenoid.
Ever notice that there's so many high performance parts available for GM products?
Did you ever think that maybe they NEED them?