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Discussion Starter #1
If i jump in my car 90 lebaron 3.0 , start it and drive. It stumbles and the rpm drop at the stop sign at the end of the block. Is my idle control motor bad or something else.

98% of the time i use the remote start so i dont witness this happening too often.
 

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Check fault codes.
 

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I'd suspect the coolant temp sensor. There may be 2, a simple single wire one running to the gauge and a second with 2 or more wires that tells the computer the engine is cold and needs a richer mixture until it warms up.
But like Bob says, check the codes to see if there is a clue there.
 

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Ditto, coolant temp sensor, fault code check, which may or may not be shown.
 

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A stumble when cold could indicate a vacuum leak. Check out all of the hoses and connectors. I can't recall if these motors had an EGR, but if it is stuck partially open it would also be a vacuum leak.

Hope this helps,

Gerry G.
 

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Discussion Starter #6
my sensor is probably 2 years old. Unplugged it runs horribly .
I will check for leaks There isnt a whole lot of hoses to check. My car is egr free. That came on later years.
 

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There is a hidden base idle screw you can adjust to raise the base idle.
If the IAC is weak/dirty etc. you can experience these symptoms.
Everyone will tell you to fix/clean/adjust your AIS and that's fine but I always raise my base idle manually.
I like to raise my cold base idle, not the warm idle speed.

Thanks
Randy
 

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I would not tamper with that screw. Fix the problem correctly. The IAC along with the PCM should be in control of the idle speed, not the hard stop screw.
 

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There is a hidden base idle screw you can adjust to raise the base idle.
If the IAC is weak/dirty etc. you can experience these symptoms.
Everyone will tell you to fix/clean/adjust your AIS and that's fine but I always raise my base idle manually.
I like to raise my cold base idle, not the warm idle speed.

Thanks
Randy
It is NOT an idle screw. It's for adjusting air flow, not idle speed, and there is a specific factory procedure for it. You're just covering up another problem by tampering with it.
 

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Idle speed is controlled by the computer watching RPM through the distributor (cam/crank position sensor). It is not an idle speed screw.
If you mess with the 'minimum air' screw, the computer will just back off the AIS until proper speed is reached. That screw is set at the factory and will require a special tool with the scan tool to reset it. You should never have to touch the screw.
If it can't reach the proper idle speed, the problem is elsewhere.
 

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I see I was correct when I said:
"" Everyone will tell you to fix/clean/adjust your AIS and that's fine but I always raise my base idle manually.""

Its funny how everyone here is so stuck on not trying simple free, reversible, 2 min. adjustments like this that require no special tools or knowledge to deal with an old car with an annoying problem.

Many guys who convert older draw through 2.2 Turbos to Intercooled use the very same 3.0L throttle body when up grading don't even use the AIS at all as the electronics differ. Call it what you want but setting the hot base idle with the base idle screw has no ill effects and doesn't set any codes.

I'm curious what scary problems you guys had when turning that screw...

Thanks
Randy
 

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It is just treating the symptom, not the real problem. The 'Minimum Air' screw should not need to be tampered with. If it does need adjustment, there is a service procedure for setting it correctly.
OBDII vehicles can set P1294 from a tampered screw:
http://engine-codes.com/p1294_chrysler.html
I don't think that your 'stumble when cold' has anything to do with this screw.
 

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I see I was correct when I said:
"" Everyone will tell you to fix/clean/adjust your AIS and that's fine but I always raise my base idle manually.""

Its funny how everyone here is so stuck on not trying simple free, reversible, 2 min. adjustments like this that require no special tools or knowledge to deal with an old car with an annoying problem.

Many guys who convert older draw through 2.2 Turbos to Intercooled use the very same 3.0L throttle body when up grading don't even use the AIS at all as the electronics differ. Call it what you want but setting the hot base idle with the base idle screw has no ill effects and doesn't set any codes.

I'm curious what scary problems you guys had when turning that screw...

Thanks
Randy
Again, it is NOT an idle screw.
All you are doing is covering up another problem and not solving it.
Not everyone is saying clean/fix/adjust the AIS. And the AIS doesn't get "tired" or "wear out" or "get weak". It's a stepper motor. There could be MANY other causes for this trouble, and the OP still has not checked, or at least posted results of a code check, despite it being suggested four times. It's always the best, first good starting point.
 
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I see I was correct when I said:
"" Everyone will tell you to fix/clean/adjust your AIS and that's fine but I always raise my base idle manually.""

Its funny how everyone here is so stuck on not trying simple free, reversible, 2 min. adjustments like this that require no special tools or knowledge to deal with an old car with an annoying problem.

Many guys who convert older draw through 2.2 Turbos to Intercooled use the very same 3.0L throttle body when up grading don't even use the AIS at all as the electronics differ. Call it what you want but setting the hot base idle with the base idle screw has no ill effects and doesn't set any codes.

I'm curious what scary problems you guys had when turning that screw...

Thanks
Randy
It's about doing things right the first time and not masking up a problem by creating another. It's what separates a technician and a schmuck.
 

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Well I must say, you guys have brought me a fresh understanding of "not being able to think outside the box"

The minimum air screw is not something magic, it just allows the engine a minimum amount of air, not quite enough to idle.
The IAS electronically supplies the engine with enough extra air to idle, and if there is a situation where it can not allow enough air it can be assisted by turning the minimum air screw to allow said idle.

As mentioned its a simple, free, reversible, 2 min. adjustment that require no special tools or knowledge.

Older vehicles such as this 3.0L, and the turbo engines with the same style throttle body, will run fine without even having the AIS connected, if the magic screw is turned enough to allow a little more than the "minimum air".
(Another AIS must be plugged into the engine harness to tell the computer its involved in maintaining a perfect idle.)
The last part is only relevant to someone who is converting an older draw through turbo to blow through and finds the AIS connectors are different.

Its not uncommon for shops/mechanics to misunderstand these cars, and after years of hearing people spending money on their car, only to have it returned no better or even worse, I try to share my findings, and not call others SCHMUCKS.

My findings are based on my own personal experiences. I have turned many screws on these older models, and have been thanked every time.

Sorry to the O.P. for cluttering up your thread, best of luck!!

Thanks
Randy
 

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It's magic! It's mystical!

Older vehicles such as this 3.0L, and the turbo engines with the same style throttle body, will run fine without even having the AIS connected, if the magic screw is turned enough to allow a little more than the "minimum air".
(Another AIS must be plugged into the engine harness to tell the computer its involved in maintaining a perfect idle.)

It's hack!
But the original problem remains, masked, possibly to cause more problems later.

Again, first step is to DIAGNOSE CORRECTLY. That includes checking fault codes and thinking through all causes. AIS is only one possible cause, there are many others. Do not be distracted by the man behind the curtain.
 

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It's hack!
Absolutely, some hacks have proven very successful.
Some of us who like to learn have hacked a few things.

It wasn't until post 8 after all the normal suggestions that I offered something to consider.

I have hacked several things on my Omni alone, Caravan front brakes, Daytona discs on the back,
manual boost control, 6-12-18-24 psi via a heater fan switch mounted on my shifter, cruise control holds steady to 120 mph, A/C charged with RED TEK, idle speed by magic screw...

I better not mention using 429 Ford pistons in my 500 in. Chrysler R.B. engine !!

Thanks
Randy
 

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Hack, not meaning innovative or creative problem-solving, but butchering and covering one problem with another.

Again, there has been no proper diagnosis yet. Therefore, no solution can be recommended yet.
 

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Discussion Starter #20
Sorry for not checking my codes yet. I turned that screw a long time ago to get my idle to go up. It was way too low.
I have obd1 it flashed 5 time and then 5 more times.
 
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