CEL on and idling hard at startup

Generalcuz · Apr 13, 2007

My check engine light came on and the XJ is idling hard at startup, but then it will smooth out after kicking it up to 2000 rpm once. Anyone know this symptom? I was thinking o2 sensor. Let me know your thoughts. It's friday, paycheck is in and wrenches are spread out on my workbench. :clap:

UNCC_99XJ · Apr 13, 2007

Year? Mileage? What engine?

If it's 96+, run it down to autozone and have them pull the code (they will do it for free). Then go from there.

Generalcuz · Apr 14, 2007

It is a 1996 XJ with a standard 4.0. Been a great vehicle this past year. I am currently at 149,982 miles on the motor. Gonna take a pic this weekend when it kicks the 150 mark.

Blaine B. · Apr 14, 2007

Throttle position sensor?

Get the code first though.

tupton · Apr 14, 2007

If it throws a "missfire at cylinder #3" then you have just experienced the great "heat vaporization issue" that the late model 4.0's experience after a hot restart. Search.......

Generalcuz · Apr 14, 2007

Okay, I will begin with the code thing tomorrow. On my way home tonight, the CEL went out. I am going to begin calling my XJ the "Rubix Cube". Secondly I will check out the throttle position sensor.

Blaine B. · Apr 14, 2007

tupton said:
If it throws a "missfire at cylinder #3" then you have just experienced the great "heat vaporization issue" that the late model 4.0's experience after a hot restart. Search.......

Yep, fix is heat-shilding over the injectors and fuel rail. You can make your own out of regular heat shileding or the dealer has a pre-cut heat shield for ya.

UNCC_99XJ · Apr 14, 2007

tupton said:
If it throws a "missfire at cylinder #3" then you have just experienced the great "heat vaporization issue" that the late model 4.0's experience after a hot restart. Search.......

However, i'm almost positive that was a 2000 and 2001 issue.

tupton · Apr 14, 2007

They say it is a 2000 and 2001 issue but I have talked to several others with 96 and up and they have has it happen to them also.

UNCC_99XJ · Apr 14, 2007

tupton said:
They say it is a 2000 and 2001 issue but I have talked to several others with 96 and up and they have has it happen to them also.

Interesting. Never heard of it happening to other's with 96-99's. Never had an issue such as that with mine, and it's seen some pretty hot weather in its time with me...

CEL on and idling hard at startup

Generalcuz

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UNCC_99XJ

Twisted Up

Generalcuz

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Blaine B.

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tupton

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Generalcuz

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Blaine B.

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UNCC_99XJ

Twisted Up

tupton

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UNCC_99XJ

Twisted Up

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