What is the issue?

 

By the look of it, you're idling about 600 RPMs. And your charging system is working great too.

Do you have some kind of issue?

 

Jeep is idling rough. Around 500rpm and then drops when at a full stop. I've replaced 1) air intake temp sensor 2) IAC 3) TPS 4) map sensor. I've also replaced the crankcase vacuum line. The jeep idle is the same and inconsistent. Feels like the jeep engine would die at a stop light but it just idle at 300rpm at times.
I've tried spreading baking soda to see if a vacuum leak somewhere but did not find the issue. Any suggestions would help. Thanks

 

1) it could be useful for people to know the model year.
2) Any codes?
3) Baking soda?????!!.

 

Yeah, I have some questions.

 

2000 xj.
baking sodar sprinkle around the vacuum lines.
No codes.
Jeep seems sluggish and idle below 500rpm most of the times. I believe normal idle should be 700rpm.
Can't figure out what the issue is.

 

Is this only an idle issue? How does it drive? At higher rpms does it missfire or hesitate? Whats your temp gauge at when this happens? Need more info.

Limp it to auto parts store and have them scan for codes.

 

My wife's 4.0 ZJ did this. It would drive seemingly fine, but started dropping to 300rpm when I came to a stop. It would hunt around too, and feel like it was going to die.
I noticed that the onboard computer was reporting terrible gas mileage (couldn't get above like 8mpg), and I eventually realized that gas was dripping out of the exhaust!

In our case it was the upstream O2 sensor. Finding a decent new one can be difficult, but I went with Walker brand and it's completely back to normal now.

 

I keep noticing a recurring theme with O2 sensors and the "Walker" brand being the ones that work - seemingly every time.

 

thank you Brynjaminjones. I will look and see if this is it. The symptoms is exactly how my XJ is acting. I'll provide an update once it's replaced.

 

I replaced the 02 upstream sensor and it is still idling at 500rpm and below at a stop. I'm at a lost to what it could be.

 

Did you ever get it scanned for codes?

 

seems to idle a bit better. smoother. No codes. here are the pictures.

 

Using the live data function on your scanner, have you confirmed the idle rpm vs what your tach is reading? Reason I mention is your tach looks similar to mine (from memory) and mine idles fine. Does it feel like it idles low (struggling) or are you just going by the tach? I think I have my scanner with me, when I go out for lunch, if I do have it, I'll hook up and compare actual idle rpm vs what tach shows.