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Discussion Starter #1
Ok Have an 88.It is not my daily driver so for the past couple of weeks it has been sitting in the drive,I go to start it today,ANd holy SH*T its idling at like 2500 -300 RPMS and won't kick down,When it did ( alittle after about 10 minutes )I put it in drive.Rpms jacked up again and I was almost like spinning my rear tires on the icy street with the brakes on, Dam near took out a parked car,Parked it on the side of the road and walked back home,ANY HELP.I am kind of new to the BRONCO thang, Been wheelin J#*PS ,,,HOPE its simple
 

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To take it back home pull the harness off the IAC and adjust the throttle blades like you would a carb, with the stop screw. A fuel-injected SBF can turn at very very low rpms and still move the vehicle, I've had the 302 in my Lincoln so slow I can damn near hear every cylinder firing and it could still idle in gear. As far as reason for the stupid high-idle - I have the very same issue with the Townie, been told that it may be the ECT or air-charge sensors going bad, I place my bet on the air-charge cause when it started acting up it was only with high-humidity in the air. Haven't gotten around to replacing those as my car don't even have a battery now (F150 uses it, will get a new one for the Townie when summer comes), but maybe tis something you also should look into?
 

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Ok Have an 88.It is not my daily driver so for the past couple of weeks it has been sitting in the drive,I go to start it today,ANd holy SH*T its idling at like 2500 -300 RPMS and won't kick down,When it did ( alittle after about 10 minutes )I put it in drive.Rpms jacked up again and I was almost like spinning my rear tires on the icy street with the brakes on, Dam near took out a parked car,Parked it on the side of the road and walked back home,ANY HELP.I am kind of new to the BRONCO thang, Been wheelin J#*PS ,,,HOPE its simple
Did you try searching at all for idle problems? There was just one on this same page.

To take it back home pull the harness off the IAC and adjust the throttle blades like you would a carb, with the stop screw. A fuel-injected SBF can turn at very very low rpms and still move the vehicle, I've had the 302 in my Lincoln so slow I can damn near hear every cylinder firing and it could still idle in gear. As far as reason for the stupid high-idle - I have the very same issue with the Townie, been told that it may be the ECT or air-charge sensors going bad, I place my bet on the air-charge cause when it started acting up it was only with high-humidity in the air. Haven't gotten around to replacing those as my car don't even have a battery now (F150 uses it, will get a new one for the Townie when summer comes), but maybe tis something you also should look into?
:twak

You don't mess with the BASE idle adjust unless there's a reason to. If something is changed, it's electrical and fuel injection related, and he needs to figure out what caused that.






Start with pulling codes.
 

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Step 1: Pull codes
Step 2: Use the search feature at the top of the page.
 

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Discussion Starter #6
walked down to the Bronco ,I had to us my battery jumper box.It started fine without the high RPM's about 1500-2000.And was able to drive it back home idled.But when I did park it I gave it alittle gas,RPMS went up ( of course ) ,ANd slowly dropped down to normal,It does sound to me like something is sticky ?? maybe I.A.C ITs dark have to get the kids to bed I'll check tomarrow,,THANKS EVERYONE FOR ALL YOUR ADVICE
 

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Could be a sticking IAC. You can try cleaning it, but generally, when they're done, they're done. I've never had such a smooth idle since I replaced mine. Truck doesn't hunt for idle at all, and only if I really sharply let off the gas in certain situations does it just barely recover.
 

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Discussion Starter #8
What do you mean" hunt for idle" are you saying that when you do let off the gas it does NOT go to an idle immedetlly ? Sorry dude it just kind of freeks me out that last night idle jumed so high,And now it idles OK,Just like I said when parked and O goose it,It doesn't kick down right away,Even after warmed up
 

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Yeah... basically it's like the IAC is always a second behind where it should be, so it's too open, or too closed, and always overshooting exactly where it should be.

I believe the programming is setup so that as the TPS senses the throttle closing, the EEC starts opening up the IAC a little to prevent a stall, and opens farther and farther the more and more you let off the gas. When you're at closed throttle, that's when the IAC starts closing back and searching for your idle, which is 660 rpm.

Sometimes with an extremely sudden close of the throttle at low speeds where driveline speed doesn't assist the engine, a sudden close of the throttle doesn't give the IAC enough time to catch back up, and thus your rpms drop real low, and then recover after a second or so.
 

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Cool so its kind of normal for it to kick down after a secong or 2..THANKS AGAIN DUDE

Yeah, just as long as the idle ends up back at ~650rpm, you're fine. The only time it's a problem is when it doesn't, or takes too long to return, and you're fighting it at a stop light or needing to put it in gear, or something like that.
 
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