low idle issue
 

Ok so my xj idles real low and the lights flicker at the same pace... what would cause this? I seen some threads and they said the battery but my battery and alternator are both new... does it sound like a vacuum leak maybe?.. someone else said distributor?

What year and drivetrain do you have ?

89 4.0 xj

Did you install the new alternator? Take it and have it tested. These are sure symptoms of an alternator going out.

Start with thorough cleaning of your throttlebody and fuel system.

Carb/choke cleaner and bottle of Seafoam.

While you are at the parts store buying things to throw at it, ask the guy to throw a tester on it and see what the alt and battery is running. Have them test the whole charging and starting system. I have seen alternators go bad quickly and if you installed a remanufactured one its not out of the question. There are a list of things you could do but its all in vain if you dont start simple and have the system tested.

I already seafoamed her... ill go and have the alternator and battery tested later... I started having this problem after I changed my valve cover so I'm assuming it could he s vacum line I might have missed but everything looks hooked up correctly... if anyone could post a pic of the top of their 4.0 engine bay I would appreciate it... I just want to make sure everything is hooked up

One thing I did notice is it gets progressive worse when it warms up.... not sure if that helps

Maybe an o2 sensor but that should not cause flickering lights and low idle. At least I wouldnt think so that is why I still think your Alt is going out.

I'll have it tested