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Old 06-03-2010, 03:58 PM   #1
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Very Low idle.....

I no this question has been asked like a thousand times, but i can't find the threads...
My TJ has a very low idle almost to the point of stalling, it shakes a lot and it feels like it wants to stall.
Can anyone help me out and tell me how i can fix this?

I no my way around carb. engines, and how to adjust the idle on them, but i don't no to much about fuel injected idle adjustments..
And suggestions!

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Old 06-03-2010, 04:50 PM   #2
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Try cleaning the throttle body and IAC (Idle Air Control). Make sure you clean IAC passage inlet, IAC module connectors. You can also remove the IAC module and clean it as well.

Attachment 19911

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Old 06-03-2010, 05:13 PM   #3
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Is it the same way on a 4 Cyl.
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Old 06-03-2010, 05:41 PM   #4
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Exactly the same!
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Old 06-03-2010, 07:39 PM   #5
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i had a high idle on my old 97, turned out to be bad throttle position sensor.

i hope its that simple for ya
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Old 06-03-2010, 07:46 PM   #6
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The IAC is what provides the engine with all its air at idle so when you have idle issues, odds are it's a dirty IAC. Clean the interior of the throttle body with an aerosol throttle body cleaner with the engine running and get some of the spray into the idle air control passage inlet so it will be drawn through the IAC port. In fact, it is the IAC and computer that controls the engine rpm, there is no idle adjustment.

If it's not a dirty IAC, the next thing to be suspicious of would be the TPS (throttle position sensor). However, if it is the TPS, it cannot be cleaned like the IAC can, it must be replaced when it goes bad.
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Old 06-07-2010, 04:13 PM   #7
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The IAC is what provides the engine with all its air at idle so when you have idle issues, odds are it's a dirty IAC. Clean the interior of the throttle body with an aerosol throttle body cleaner with the engine running and get some of the spray into the idle air control passage inlet so it will be drawn through the IAC port. In fact, it is the IAC and computer that controls the engine rpm, there is no idle adjustment.

If it's not a dirty IAC, the next thing to be suspicious of would be the TPS (throttle position sensor). However, if it is the TPS, it cannot be cleaned like the IAC can, it must be replaced when it goes bad.
If it is the TPS, Is there any way for me to find out for sure before i buy a new one, or will i have to buy a new one and hope i didn't waste my money on it?

And i have been experiencing that when ever i go to start my jeep, and i back out of my drive way and start to build of speed in 1st gear, it starts to sputter and backfire and wants to stall. When that happens, i push down the clutch and rev up to about 4000 RPM's and then start going again and it doesn't happen again until i shut it off for a little while. What could be causing this? a bad fuel filter?
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Old 06-07-2010, 04:17 PM   #8
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When was the last time you replaced spark plugs, distributor cap and rotor?
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Old 06-07-2010, 04:20 PM   #9
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Originally Posted by 97'wrangler View Post
If it is the TPS, Is there any way for me to find out for sure before i buy a new one, or will i have to buy a new one and hope i didn't waste my money on it?

And i have been experiencing that when ever i go to start my jeep, and i back out of my drive way and start to build of speed in 1st gear, it starts to sputter and backfire and wants to stall. When that happens, i push down the clutch and rev up to about 4000 RPM's and then start going again and it doesn't happen again until i shut it off for a little while. What could be causing this? a bad fuel filter?
If the problem isn't cured by cleaning the IAC as recommended as a first step, odds are very good the problem is caused by the TPS. I always like to try the easist/cheapest/most-likely fixes first & only after that doesn't work, go to something that costs more $$$. Cleaning the IAC as a first step & only buying & installing a new TPS afterwards if cleaning the IAC doesn't fix it seems like a good way to go.
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Old 06-07-2010, 07:38 PM   #10
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My spark plugs not to long ago,and they look in fine shape. but i'm not sure about the distributor, is there a way to check and see if i need to change it without buying a new one first?
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Old 06-07-2010, 07:48 PM   #11
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Have you cleaned the IAC that was first suggested to you last Thursday? If not, why are you asking about things like the distributor when you haven't yet tried the free and easy stuff that is the most likely to be causing your problem?
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Old 06-07-2010, 09:28 PM   #12
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I have a customer like that --- "I don't want it to be that simple."

Now I just send him down the road.
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Old 06-08-2010, 06:40 PM   #13
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i have already cleaned it... didn't help!
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Old 06-08-2010, 07:03 PM   #14
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You can remove the distributor cap (make sure to mark the wires!!) and clean the pins inside. Clean the rotor as well. See if that helps.

Also, the new ones are not very expensive. Distributor cap and rotor total are less than 30 bucks. If you are going to get new distributor cap and rotor, get the ones with brass contacts. They will last a lot longer.
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Old 11-16-2010, 09:49 PM   #15
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Hi everybody.
I have a 1993 manual Jeep Wrangler. It started to develop problems during the last week or so...
Everytime I am in neutral or standing on the clutch the idle goes down as much, that everynow and then ist stall. My housemate knows his way arond engines and he said to adjust the idle, but he never done it on a jeep and couldn't figure it out.
There is also a loud clicking coming from the engine when it is running. Could there be a connection??
We also cleaned the spark plugs (is that how you call them?) but it doesn't help.

I would really appreciate your help!!
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Old 11-16-2010, 10:00 PM   #16
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Quote:
Originally Posted by Red/Black View Post
Hi everybody.
I have a 1993 manual Jeep Wrangler. It started to develop problems during the last week or so...
Everytime I am in neutral or standing on the clutch the idle goes down as much, that everynow and then ist stall. My housemate knows his way arond engines and he said to adjust the idle, but he never done it on a jeep and couldn't figure it out.
There is also a loud clicking coming from the engine when it is running. Could there be a connection??
We also cleaned the spark plugs (is that how you call them?) but it doesn't help.

I would really appreciate your help!!
you should go to CJ forums since TJ is all fuel injection. YJ is carbed so its kinda different.
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Old 11-16-2010, 11:05 PM   #17
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When you first start it, the computer isn't on line yet. A vacuum leak can drop the idle till it warms up a little and the computer starts working - compensating for the vacuum leak.

Test it by choking off the air at the TB with your hand when you first start it cold. If it runs better for a moment, it's a leak.

Spray a burnable carb cleaner around the TB baseplate, the intake manifold gasket, and the hoses going to the vacuum fitting on the manifold. Look for an RPM change when you hit the leak.

Testing and diagnosing is cheaper and more effective than throwing parts at it.
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Old 02-26-2011, 10:01 AM   #18
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i know this thread is a little old but wanted to thank you all anyway! g/f went to drive my 99 tj this morning and it wouldnt start for her, i got it running but had to use the gas a bit to get it going, and it was idling around 300rpms, if you can even call that an idle lol, anyway found this thread and tried cleaning out the IAC with some throttle body spay, died the first few times but i started giving it some gas with the throttle while spraying it after about 10 short sprays it was running perfect, drove it for 5 hours on the highway after that no problem, thanks!
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Old 03-28-2011, 05:18 PM   #19
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so did it ever work out for you '97 wrangler?
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Old 06-28-2012, 10:49 PM   #20
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thanks for the help i have a tj and frustrated me to death
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Old 11-10-2012, 07:38 PM   #21
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What kind of throttle spray for the IAC?

I have the same problem, low idle and some times it sputters out and dies. Othre times it runs fine. I just went to Advanced Auto Parts and they said they didn't have any spray. I didn't want to get the wrong stuff. Can I just use carb cleaner. I don't want to ruin the IAC or any O2 sensors. I plan on taking it apart and cleaning it. Hopefully that will work.

TIA
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Old 11-10-2012, 07:42 PM   #22
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Advanced Auto Parts didn't have an aerosol throttle body cleaner? You sure about that? If you couldn't find it, they're either out of stock or you're looking in the wrong section. A sensor-safe aerosol carb cleaner is essentially the same thing if you can't find the aerosol throttle body cleaner.

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