When AC is on and idle drops really low, too low

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I'm doing this for a friend so work with me

Alright when my friend turns the AC on in his '95 Probe(non-GT) the idle will drop soo low the car starts to shake really bad and the engine almost dies. Now i've reset the idle and still nothing. What is the problem? Thanks in advance.


posted by  kidrcth

Most likely a bad, sticking or clogged IAC. The good news is now you've made the problem worse. The screw you turned is only a throttle stop, NOT for adjusting idle speed. So when you do fix the problem now the PCM will be confused as to why the TPS says the throttle is partially open. I just love it when people work on things they don't know about.

posted by  vwhobo

well thanks, now if i'm a newbie to engines and such, where would the IAC be? And for one thing that might be the problem, the guy that he got the car from said it has previously been driven into a body of water, sooo that might have done it correct?

and if i want to put the idle back how would i do that?

posted by  kidrcth

If you're a "newbie to engines and such" you shouldn't be turning screws unless you know what you're adjusting and why. The first step is to get yourself a good manual, read it, look at the pictures and follow the directions.

Now before you waste my time calling me an asshole or whatever the simple fact is a modern car is a very complex machine with many complex systems. Nobody should be taking shots in the dark and adjusting this or replacing that without the required knowledge. Start at the beginning and work from there.

To answer your questions maybe and the manual will tell you.

posted by  vwhobo

alright i'm a newbie to most of an engine but i didn't really remember what an IAC did and where it was, or what it looked like. But i did know wth a idle screw is and such. I have a Trans Am of my own and i work on it all the time. I changed heads the other day, before that added a new super coil, and a new exhaust 2 years ago. now could you please help me fix the thing rather than get on me for my mistakes , please.

ps: i never called you an asshole, not even in my head.

posted by  kidrcth

Read this and then you can call me an asshole.

1. You adjusted the idle speed with the throttle stop screw.

2. You asked me how to adjust it back.

3. You state you know what an idle screw is.

Do you see any contradictions? I most certainly do. It's called tough love buddy, get yourself a manual and take it from there. At that point if you have any questions I'll be happy to help.

posted by  vwhobo

ok i did a small contradiction but what i meant by how to fix it back was, hom many turns out from all the way in do i do? if you know of coarse. Now before this reply i was looking at other sites


that is the site i used to figure it out, please tell me if it gives you decent info on how to fix it, then you know we can move on to something new.

posted by  kidrcth

1. There's a reason it's called an adjustment. It varies from car to car based on manufacturing tolerances. I don't know where you started so I can't tell you where to put it back. The MANUAL will give you the proper procedure.

Yes, the site shows the procedure quite well for a Vectra. You are working on a Probe. The procedure will be the same however the parts will look somewhat different and be in different places.

posted by  vwhobo

alright thanks i think i may be able to manage finding it now when i go over to his house next. Now for the part about needed to get a gasket, is there anyway around that, is there a pro way to get the gasket off good? If not where online would be a good place to price shop for it? thanks for your help

posted by  kidrcth

never mind d00d i found the perfect website for the exact model and everything and there is no gasket from the looks of it, if you want to check it out,


thanks for all you help

posted by  kidrcth

all you needed was a can of carb. clean.
now you opened a can of worms :D

posted by  (o) (o)

not really i know exactly what todo now. I'm a knetic learner, meaning have to see things, and i cant do stuff like that without pictures. I just can't. I needed to see where the thing was and how it opened up and thats all, i could figure out what i needed to fix it easily.

posted by  kidrcth

Assuming that's actually the problem. Now all you have to do is figure out what caused the IAC to clog, if that is the case.

posted by  vwhobo

now if you would of read it all the way i said the previous owner drove it into a body of water which may have done exactly that.

but if not then what else could do more than that, only thing i can think of might be dirty fuel or bad air filter.

posted by  kidrcth

Now if YOU would read it all the way I responded to that question when you asked it so I must have read it. You seem to know an awful lot for a self described newbie, especially since you didn't even know what an IAC was a few posts ago. Would the fact that "it has previously been driven into a body of water" cause a problem with the IAC? Not likely. And if you already knew what the problem was why did you come here looking for help? Oh yeah, I already know the answer to that.

posted by  vwhobo

you know what i'm tired of you guys rankin like this. I never said i knew what the problem maybe, and the car being driven into a body of water means that someone was stupid enough to drive the car into a river or something like that. I said that the river thing might have made the clogging be done in the IAC.

se peace and i'm gone!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
yeah just like that

posted by  kidrcth

Damn I'm heartbroken!!!!!!!!!!!!!!!!! :?

posted by  vwhobo

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