Extremly High Idleing During winter starts -- 93 Lumina 3.1 -- Throttle Position Sens

[starla3366]

When ever I wake up in the morning to go to work (winter weather). I start the car to warm it up, and the car Idles so high, I don't know exactly what rpm's, I don't have a gage for that. So, I let it run for a minute, then I put it in reverse or drive for a minute with the brake on and I can feel the power I'm trying to hold back. Then when I put it back in park the car is idleing just fine. I have to do this every morning before work. It's getting kind of old and I think I let it go a little to long. It did it all last winter, and it hasn't done it since late spring. Let me remind you, I live in the frozen tundra state of Maine. The winters get pretty cold. I think it has something to do with the choke, but I don't know where it's at.


The car is a 93 Lumina 3.1. No it's not a EuroSport.

Any help would be nice.

[Kooterskkar]

Theres no choke on a feul injected engine. Id start with the IAC. Also check to make sure you dont have any vacuum leaks.

[richtazz]

I agree with Kooter, you probably have a sticky IAC motor. It acts like a choke and will let too much air in when the engine is cold if it's stuck open, and cause the high idle you describe. Then it unsticks, and all is happy.

[starla3366]

Originally Posted by Kooterskkar

Theres no choke on a feul injected engine. Id start with the IAC. Also check to make sure you dont have any vacuum leaks.

What does IAC stand for? I probably know what it is, I just never heard it abbreiviated like that.

[Kooterskkar]

Idle air control, Its a valve taht opens and closes depending on how much air the engine needs to stay idleling. It pretty much creates a vacuum leak.

[starla3366]

Why did my father in-law tell me not to screw with this IAC? Does he know something I don't? He tells me "no one messes with the IAC, no one!"

[richtazz]

You can pull the IAC out and clean the pintle (the little cone piece), but don't move it in or out, or you'll mess up it's calibration. The pintle gets gummed up with laquer deposits from the fuel, and will stick in it's bore. If it continues to stick, it will ruin the little solenoid that moves it in and out and will have to be replaced.

[jeffcoslacker]

Originally Posted by richtazz

You can pull the IAC out and clean the pintle (the little cone piece), but don't move it in or out, or you'll mess up it's calibration. The pintle gets gummed up with laquer deposits from the fuel, and will stick in it's bore. If it continues to stick, it will ruin the little solenoid that moves it in and out and will have to be replaced.

Sounds like a little well placed O2 sensor safe spray carb cleaner might be the answer? You gotta get that taken care of-you'll tear the motor mounts up if you keep dropping it in at high idle. Hard on the tranny and brakes, too.

[starla3366]

Originally Posted by jeffcoslacker

Sounds like a little well placed O2 sensor safe spray carb cleaner might be the answer? You gotta get that taken care of-you'll tear the motor mounts up if you keep dropping it in at high idle. Hard on the tranny and brakes, too.

I agree, this needs to be taken care of. Jeff, what your saying is to spray carb cleaner on the O2 sensor? If that's the case, I might as well just replace the damn thing.

Thanks

[jeffcoslacker]

No not the O2 sensor, you just have to use O2 sensor safe cleaner on all newer cars. The old carb cleaner would foul the sensor. I was saying to remove the IAC and spray the pintle and let it soak in, then spray again to blow away any residue. With the pintle seated, it may not get to where the sticky part is. Maybe you could connect it to the wire for it, and turn the ignition on to get it to open, then spray it. Anyway, once it is soaked in cleaner, I'd try to put it back on before it dried, and start the motor. That would allow for the residual cleaner to be drawn through the unit, giving it a more internal cleaning. Never tried it though, always just replaced 'em.