Author Topic: Rough Idle, Stumble, Just After Cold Start, 97 TJ  (Read 4289 times)

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Offline Tr00b

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Re: Rough Idle, Stumble, Just After Cold Start, 97 TJ
« Reply #15 on: April 19, 2012, 10:27:59 PM »
When I had this problem... new exhaust manifold, intake/exh manifold gasket, (IF you have obvious exhaust leaks) upstream o2 sensor, cleaning the intake air temp sensor (looks like bolt with a wiring harness coming off the manifold near the firewall), all contributed to eliminating the cold stumbling problem. Biggest things? o2 sensor and IAT. My IAT was plugged with black crud from the PCV something awful.

My original cat was hollow, putting a cheap one on and the downstream o2 cleaned up the CEL.

Offline grumpygy

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Re: Rough Idle, Stumble, Just After Cold Start, 97 TJ
« Reply #16 on: April 20, 2012, 08:26:51 AM »
When I had this problem... new exhaust manifold, intake/exh manifold gasket, (IF you have obvious exhaust leaks) upstream o2 sensor, cleaning the intake air temp sensor (looks like bolt with a wiring harness coming off the manifold near the firewall), all contributed to eliminating the cold stumbling problem. Biggest things? o2 sensor and IAT. My IAT was plugged with black crud from the PCV something awful.

My original cat was hollow, putting a cheap one on and the downstream o2 cleaned up the CEL.

Wonder I had an Exhaust leak from a busted off bolt, I could hear it only till it warmed up then it was gone.  Could the same thing happen with the intake and a loose or broken bolt.
94 YJ, Cool Air intake, 19lb Inj, 4.0 Throttlebody with spacer,  31/10.50/15's

Offline AWK

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Re: Rough Idle, Stumble, Just After Cold Start, 97 TJ
« Reply #17 on: April 20, 2012, 03:15:44 PM »
Interesting,  since it set the CEL it has been running great.  I have watered it down and no issues there.   Rain here tomorrow, I'll see what that does.   I will need to hold off on the convert till next year.
Awk