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4.0 High Idle


Shikai2070

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Sep 28, 2020
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Location
Vancouver B.C
Vehicle Year
1992
Make / Model
Ford Ranger
Transmission
Manual
Have a 92 ranger with a 4.0l. Dealing with a high idle issue. Around 1500rpm. Tried cleaning the IAC and it didnt seem to help. Can verify it moves when 12v is applied to it. If I unplug the iac the idle drops down to 1000 rpm or so.
 


Rock Auto 5% Discount Code: 7FA902352B4C01: April 5th, 2021

Eddo Rogue

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Location
Burbank,CA
Vehicle Year
1993
Make / Model
Ranger 4x4
Engine Type
4.0 V6
Engine Size
OHV
Transmission
Manual
2WD / 4WD
4WD
Total Lift
skyjacker front leveling kit
Tire Size
31-10.50R15
My credo
Crossed threads are tight threads.
I had a high idle issue, apparently its common on the 4.0, and could be many things. Mine turned out to be the throttle body. I taped the hole shut on the throttle plate and it dropped my idle nicely, so I filled it in with solder and drilled a smaller hole, idled and ran great until I was able to replace it.

Anyways if you want a quick test, you can try taping over the hole on the throttle plate and run it.
 

Shikai2070

New Member
Joined
Sep 28, 2020
Messages
4
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Location
Vancouver B.C
Vehicle Year
1992
Make / Model
Ford Ranger
Transmission
Manual
I had a high idle issue, apparently its common on the 4.0, and could be many things. Mine turned out to be the throttle body. I taped the hole shut on the throttle plate and it dropped my idle nicely, so I filled it in with solder and drilled a smaller hole, idled and ran great until I was able to replace it.

Anyways if you want a quick test, you can try taping over the hole on the throttle plate and run it.
Will that cause issues? Shouldnt the hole be left open if its there by design?
 

PetroleumJunkie412

2.9 Mafia
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Location
Pittsburgh, PA
Vehicle Year
1988
Make / Model
Ranger
Engine Size
2.9l Trinity
Transmission
Manual
2WD / 4WD
4WD
My credo
Give 'yer balls a tug. Fight me.
You have a vacuum leak.

Propane test or smoke machine.
 

Eddo Rogue

Well-Known Member
Joined
May 18, 2020
Messages
1,324
Reaction score
323
Points
83
Location
Burbank,CA
Vehicle Year
1993
Make / Model
Ranger 4x4
Engine Type
4.0 V6
Engine Size
OHV
Transmission
Manual
2WD / 4WD
4WD
Total Lift
skyjacker front leveling kit
Tire Size
31-10.50R15
My credo
Crossed threads are tight threads.
Will that cause issues? Shouldnt the hole be left open if its there by design?
Well on mine I think the gap between the plate was compromised. making more air than usual pass thru when closed.
This was a diagnosis/temporary fix. I did replace it with a new one.
 


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