Stalling before warm up?

[AeroBoost]

Yea, that.
99 xj 4.0 is stalling, sometimes at Idle, before it gets warmed up good.
Idle is sometimes rough but usually fine. Get out in the road, hit the gas and "pluh"....
Just stalls. RPMs drop. won't go. Then suddenly as if being kicked in the rear, it takes off and doesn't do it again.

No codes.
I've been searching for vacuum leaks but can't find one. Not to say that's not happening; just can't find it.

ideas?

 

[badmonkey]

Temp sensor??

 

[davewjcook]

No codes... Will the stall / stumble actually clear an existing code and reset your emissions tests? I had a wire feeding the computer on my LJ randomly short out that would cause the computer to reset and act like a stumble similar to yours when I stepped on it. Took forever, and 3 unnecessary new computers, to successfully track it down to a wire inside one of those thick harnesses.

 

[AeroBoost]

I don't know?
It's not throwing a light at all.
I could check and see if there's a code stored even though the light never came on.

any way to test the temp sensor?

 

[badmonkey]

Dunno. Maybe test by replacement, assuming it isn't tooooo expensive?

 

[badmonkey]

I did some Giggle searching. Two diagnoses surfaced. One matched the aforementioned temp sensor. The other.....

 

[AeroBoost]

...if i had a nickle...


looks like that sensor is gonna run me $25-$30
I've replaced more expensive parts for dumber reasons, I guess...

 

[AeroBoost]

Coolant Temp Sensor fixed it 👍

 

[badmonkey]

Coolant Temp Sensor fixed it 👍

Awesome!!

 

[AeroBoost]

Not fixed.
It was. Now it's not.
Gonna check for damaged wiring but beyond that im lost

 

[badmonkey]

Not fixed.
It was. Now it's not.
Gonna check for damaged wiring but beyond that im lost

Dambit man.

Going out on a limb. These days foreign parts are cheaper than ever, despite consumer cost. Any chance the shiny new part is tarnished?

 

[AeroBoost]

I thought about that.
Its 'new' wire.
Its gotten too close to the manifold at some point and melted the loom.
I did check on the wire during the swap and didn't see anything. Im going to strip the loom off and get a better look.

 

[AeroBoost]

I'm thinking it's the wiring to the sensor... acted up friday am. I screwed around with the wiring, checking for damage during lunch. didn't really find anything, though, I'm going to cut out a splice i'd put in. It acted up the first few minutes on the trip home.
Saturday.... nothing. no trouble.

 

[G Beasley]

Ghost in the machine is teh debil! I am chasing one in Hannah's old TJ. I wish you luck.

 

[AeroBoost]

Ghost in the machine is teh debil! I am chasing one in Hannah's old TJ. I wish you luck.

Who ya gonna call? ....ssssombody else.
I THINK I've fixed it.
I redid the splice in the wiring to the sensor.
The wiring was burned in twain once due to getting to close to the manifold. I bought a new pigtail and spliced it in.
Apparently not good enough. So, re-spliced.

It did fine this AM but it's tricked me before...