I have performed searches here and found lots of information on low idle at stop but my issue is a little different.
I am thinking weak battery.
Since I bought my 01 xj I have had weak starts and even weaker after it sits overnight.
As of 2 days ago I was driving through town and when I came to a stop, my idle dropped and so did my voltage. (This only happens at the stop and has absolutely no issues when taking off from a stop)
I finally reached the highway and drove home.
When I exited the off ramp I again had about 4 stops to go through but this time I did not have the idle issue at all.
Next morning, start her up and again with the week start and after the normal high idle drops, she starts with the idle dropping and raising and voltage issue again.
I again head to the highway, drive to work and again, once I am off the off ramp, I have no issues.
My thought is my battery is weak and is not charging properly.
I say this because after a trip on the highway its charged enough to last a few stoplights from the off ramp to my destination.
What are your thoughts?
No rough idle when moving or just after highway trip

 

Have your battery load tested, that will give you the answer. Sounds like you might be getting a new one.

 

Thanks Roler.
I'll go have it tested after work today.

 

Agreed. A marginal battery would account for both symptoms.

Load testing is the ONLY conclusive way of testing a battery.

I'm betting it fails the load test. Keep us posted!

 

Confirmed..... Bad battery.

 

Thanks for letting us know how it went. A short thread with a closure!