I recently just completed changing out my fuel injector o-rings on my stock 2.8L, replacing vacuum lines with Rodney Dickman's stainless steel, a new EGR and EGR tube. I noticed when I removed the upper plenum, the EGR tube was fractured at the joint. I went ahead and ordered on a replacement from Rodney Dickman's and installed it..

The old cold start idle was about 1500 rpm and was very stable. As the engine warmed up the idle would settle down to 850 to 900 rpm.

After completing the work my cold start high idle is now about 1100 and it drops to 850 or so after it warms up.

Is this 1100 rpm idle normal for cold start or should it be closer to 1500?

As I recall the book says 1200, but I doubt the tachometers are that accurate at this point.

Mine starts at about 1500 (indicated) but drops virtually immediately to 1200, where it remains until warmed up a little - which of course varies on ambient weather and if I start driving it or just let it idle.

As far as the tach reading... Mine is pretty accurate. With my Actron ODB-1 scanner connected in realtime mode, the reading on the scanner and the tach are within about 50 rpms of each other.

My duke is anywhere from 1200 to 3000 in the cold weather of wisconsin.