Hey guys,
I know high idle threads are all over the forum but just have a quick ? about the egr valve. If bad will it cause a steady high idle? My '92 5.0 TPI has recently been revving at about 1100 to 1500 rpm. It won't surge, it'll just stay high when I come to a stop. I recently changed my head gaskets so all seals are new and didn't notice any cracked vacuum lines. It would idle high periodically before the head job too so it isn't something new. When I pulled the egr it held vacuum when compressed while plugging the vacuum port but i haven't done any other test on it.

It has a new IAC valce and cts. It'll usually idle at 800-850 but will get stuck at 1100 or more while returning to idle. Prior to sticking at high idle it would take long to return to idle. Usually around 10 seconds.

any ideas anyone? oh and I never reset or calibrated the new IAC. Should I if it will idle fine at startup?

 

Bad EGR system can cause high idle. But don't delete it, just invest in fixing it. It's worth fixing. Then do re-adjust your IAC.