RPM's really worrying me!

[SpiffWilkie]

And of course it could also be a vacuum leak like Lola and the others said, The IAC is really a controlled vacuum leak. I was trying to provide a fresh perspective.

Yeah, gotta check for this, too. I didn't have time to look at the car over the weekend. I had to fix my wife's cruise control (Someone *cough*me*cough* accidentally left a sensor unplugged last time he was checking something under the hood).

[SpiffWilkie]

Wanted to give an update (for this thread I hijacked). I pulled the throttle body off and cleaned up the IAC and the TB. I replaced the TB seal while I was at it. None of that changed anything with the high idle. It had been very consistently keeping the idle about 2000 rpm when at a stand-still, and not really dropping below that while driving, either. Occasionally, it would drop below that when I put the car in 1st and gave it just a little gas.
Anyhow, I did the suggestion from earlier in the thread where I unhooked the brake booster line from the intake manifold, unplugged the IAC, and then put the brake booster line back on. The RPMs didn't drop like they should have, indicating a bad IAC. What's weird, though, is that the past two days since doing that, I haven't had any issues. So....not really sure what the deal was/is. It's been working fine, idling at the correct speed, etc.
I've also tested for vacuum leaks, and can't find any.

I've got my fingers crossed, hoping that the issue won't rear its head again...but I'm sure it will.

[JusteR]

Sounds like the IAC was carboned up? And cleaning it and running it open and closed helped... only time will tell. Hope I helped. I appreciate the follow-up.

[josefb134]

Haha no worries about the hijacking! I have been busy and haven't been getting any notifications on this thread for some reason. I have tried checking for vacuum leaks by spraying brake cleaner on all of the vacuum hoses and also blowing cigar smoke all over the hoses and I found no leaks. I have checked and cleaned the butterfly valve in the throttle body and the IAC and also replaced the IAC and still having the same problems. It doesn't matter what temp the engine is at or the outside temp. I am planning on trying the break booster line disconnection sometime soon and I will report back on what happened.

SpiffWilkie Any update on how it has been acting since you did the break booster procedure?

[avguy]

Holy $hit - sounds like you're saying this high idling has been happening with your Aveo for almost a full year????

[reddemonx92]

Idk how u can drive it that long with this dam problem. My automatic is having this issue and I cant stand it. Been going on for 3 weeks now. Have yet to find a solution for this issue.

[josefb134]

Yeah it just goes off and on, but when it is on it seems to never go away until I am done driving it for a bit. It it is very irritating when every time I switch gears the engine revs up to like 3500 RPMs and then bogs back down when I put it in gear again. I'm afraid the clutch is going to got extremely torn up because of it. And yeah, I would love to get it fixed but I have had two different shops run diagnostics on it and they bot told me it could be the IAC but i already replaced the IAC and nothing changed. They don't have any Idea what it is and they said they have never seen this problem under these conditions. It is soooo irritating also when coasting up to a stop light next to someone and they think I am trying to race them by revving my engine when i'm not, or even coasting through the parking lot, people think I am revving my engine at them while they are walking and it is just annoying haha I get so pissed off and just beat the **** out of the steering wheel when it just continues and continues to do it cause I have no flippin clue as to how to fix it... haha I have even tried turning my car off while coasting and while stopped (once it revs down all the way) and restarting it but it just jumps back up to the same high ass RPM's lol

[avguy]

No one in two shops could figure out this problem? Another example of why many here try to DIY whenever possible.
Have you tried the brake booster test that was posted above? Based on what SpiffWilkie wrote, it seems definitely worth trying. Also, have you carefully examined the TPS and IAC wiring and connectors? There was a thread a while ago (that I can't find now), where someone posted that a dealer replaced one of those connectors. Fixed their problem, but I don't recall the exact details on that one. How about the old favorite test spraying a bit of carb cleaner around the TB, manifold, and hoses, to see if there's any change in idle speed?
There was also a post recently from someone who found that the rubber ends of the map sensor connector were cracked. That doesn't seem like a possible reason for your problem, but it might be worth a look anyway, especially since it will only take about 10 seconds.
RPITA you have there

[josefb134]

I tried the break booster test today and the car idled back to normal after I unplugged the IAC and reconnected the break booster hose so that tells me my IAC is broken or gummed up. I also found that there is a crack/tear in my intake flex hose so I took it out and removed the Intake Air Temp Sensor and I am soaking it in dawn and hot water to get it cleaned up. I am going to use some Flex Seal to hopefully seal up the intake hose once it is fully dried. The unfiltered air could have made the IAC gunk up but the rest of the throttle body is clean so i'm not sure. When I put my finger on the hole on the inside of the throttle body behind the butterfly valve where the IAC regulates the Idle air there was a brown/orangish colored oil or something that got on my finger. I don't know what that could be but I am going to take out the IAC and hopefully clean all of that up with some throttle body cleaner. I also ordered a new IAC and should be replacing that tonight to see if it is fixed. I should have it all fixed up by tomorrow around five. I will continue to update everyone on here when I find anything new.