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Discussion Starter #1
Is there a way to adjust the engine idle speed on my '96 Cougar with a 4.6L?

It's idleling at about 500 RPM's in gear, but when you turn the steering wheel the idle drops under 500 and the engine starts to shake but recovers slightly.

When the engine is idleling in park the RPMs are about 600-700. Turning the steering wheel drops the speed down to around 500 but without the shakes.

No other engine issues, it just seems to me that the idle is a couple hundred RPMs too slow.

Is the threaded screw on top of the throttle body (where the linkage is) the idle screw, and if so, it doesn't have a slotted head on either end to turn it with.

Advice is needed.
 

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Is there a way to adjust the engine idle speed on my '96 Cougar with a 4.6L?

It's idleling at about 500 RPM's in gear, but when you turn the steering wheel the idle drops under 500 and the engine starts to shake but recovers slightly.

When the engine is idleling in park the RPMs are about 600-700. Turning the steering wheel drops the speed down to around 500 but without the shakes.

No other engine issues, it just seems to me that the idle is a couple hundred RPMs too slow.

Is the threaded screw on top of the throttle body (where the linkage is) the idle screw, and if so, it doesn't have a slotted head on either end to turn it with.

Advice is needed.
It sounds like your idle air control solenoid is not working. This looks like a small round silver can bolted to the front of the air intake plenum facing towards the front of the car. There is a harness connected to it and a short air hose that runs through a small black muffler and then to the air intake runner between the mass air sensor and the throttle body. I would suggest you pull the air hose off the solenoid and spray carb cleaner inside. Hook up hose, start car and tap on side of solenoid with screw driver handle. The solenoid is either stuck or there is no pwer going to it.

Mitch
 

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Discussion Starter #6
1. The MAF wires are clean. I maintain them every 6 months.

2. I recently removed the IAC and cleaned it thoroughly.

For testing purposes only, I did not plug the electrical harness into the IAC after cleaning it and then started the engine. It idled much worse. From that test, I figured that my Idle Air Control valve was working properly. But then again, maybe it is not working 100%.

I'm game for more suggestions. What is the MLPS? Does that have something to do with the transmission?
 

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Yes. It stands for Manual Lever Position Sensor. It is what tells the computer what the gear shifter is in. If it goes out it may think the car is in the wrong gear. So if you have it in park it may think it's in drive. Mine was going out and throwing wrong voltages. So my idle speed in park was close to 600.
 

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Discussion Starter #8
Yes. It stands for Manual Lever Position Sensor. It is what tells the computer what the gear shifter is in. If it goes out it may think the car is in the wrong gear. So if you have it in park it may think it's in drive. Mine was going out and throwing wrong voltages. So my idle speed in park was close to 600.
If it is my MLPS, is replacing it easy to do, or do I need to take it to a trans shop?
 

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For testing purposes only, I did not plug the electrical harness into the IAC after cleaning it and then started the engine. It idled much worse.
My cars wont idle at all with a working IAC unplugged...

It would barely idle with the one that "honked" for a month before it went out, tho.

(The IAC will make a noise sometimes; a cross between a goose in heat and a pipe organ... :) )

I would change the IAC out; or swap a known good one to see if it helps, if you have access to one.
 

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1. The MAF wires are clean. I maintain them every 6 months.

2. I recently removed the IAC and cleaned it thoroughly.
why do people always fail to mention these things in the original thread? :)
 
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