Revving to 3k when idle

[DANTEBRIGGS]

So a few days ago, I had my gas cap off while paint was drying. I forgot the gas cap was off and started the engine and left it on for a few minutes. I finally thought all of my bugs were fixed in this car.

About 3 minutes into running the engine with the cap off, the engine started revving to about 3k.. I remembered the cap was off and turned the ignition off and put the cap back on.. Now the problem wont go away. Any ideas?
Please help this is frustrating..

Details:
Upon start it immediately revs to 4000.
After about 10 seconds it settles and drops to 900 rpms
Then every 3 seconds or so it revs to exactly 3100 and back to 900.
(^^ this is when in neutral)

When the car is in gear, driving, you feel the revs but it is limited to where you cannot see revs on the tach, but you do feel it while driving

**It had a quarter tank of gas when it initially happened. I drove it about 15 miles and thought it might go away, but nothing. I then put gas in until it was a little above half tank.

Here is a video I took of it idle in neutral.

http://www.youtube.com/watch?v=KxxN51SQT2E

[jlevie]

It would be helpful to know what car this is.

Intake leaks, a sticky ICV, bad ICM or DME are all possibilities.

[aziza z]

My car was doing the same. Turned out to be sticky ivc. Theres a write up on here i believe that I followed to clean it up. Basically wd40 and qtips. Fixed the problem.

[DANTEBRIGGS]

Thanks for the responses.

Sorry- It is an 87' 325 (no i or e)..

I did a bit of searching and yea most seem to say ICV, but my question would the gas cap being off w/ engine on trigger a sticky ICV??

[DANTEBRIGGS]

Update: It is now revving less of a span. It was initially 800 - 3100. Now its going 1400 - 2700. Each time it has been exactly the same revs.

[Huff]

Are you sure the hose from the AFM to the throttel body doesn't have any cracks?

[DANTEBRIGGS]

Are you sure the hose from the AFM to the throttel body doesn't have any cracks?

I just checked the hose and it looks to be in very good shape. I had a buddy say that when the gas cap was off, the fuel tank pulled in some air and I just need to let it run through a bit of gas to have it go away. Thoughts?

[RobertK]

Sounds like you own an "e" car with and eta engine.

My friend just finished resolving this issue which turned out tp be a bad ICM (idle control module) its a little green relay looking box located under the dash in the glove compartment.

Its common for these to go bad and cause these kinds of idle issues.

[SpecM]

I had a buddy say that when the gas cap was off, the fuel tank pulled in some air and I just need to let it run through a bit of gas to have it go away. Thoughts?

that makes no sense

[DANTEBRIGGS]

that makes no sense

yea thats why i brought his diagnosis here.. i wanted someone to say that ^^. i wasnt sure about it..

[DANTEBRIGGS]

Sounds like you own an "e" car with and eta engine.

My friend just finished resolving this issue which turned out tp be a bad ICM (idle control module) its a little green relay looking box located under the dash in the glove compartment.

Its common for these to go bad and cause these kinds of idle issues.

is there anyway i can test the ICM? or determine if its bad before heading to the junkyard to get a new one?

[tonywonder]

the only time ive personally seen this is in my honda. i get that loping idle when i start the car up and start driving it around before letting it warm up. It also did it when there wasnt enough coolant in the system and when i didnt bleed the cooling system.

[StereoInstaller1]

I had a buddy say that when the gas cap was off, the fuel tank pulled in some air and I just need to let it run through a bit of gas to have it go away.

That is one of the silliest thing I have heard "a buddy" say.

My cell has shit reception at home. Fine elsewhere, but shit at home. Bitch at Sprint said that was because of the walls of the house...I said then would you explain why I get great signal in a goddamn MALL?

Think about it: if you have 1/4 tank of gas, you have 3/4 tank of air...there is no bladder in any normal gas tank, cap on or off has no bearing.

People get the weirdest ideas in their heads I swear!

[clydesdale]

It works in the mall because the mall has signal repeaters:drink:.
BTW, do the "i" motors have an ICM as well? My idle ramps up to 2000 randomly and is horrible with it when I turn the a/c on. I already have a new throttle body hose and icv. Can you tell me more about this ICM you speak of? Thanks.

[DANTEBRIGGS]

That is one of the silliest thing I have heard "a buddy" say.

My cell has shit reception at home. Fine elsewhere, but shit at home. Bitch at Sprint said that was because of the walls of the house...I said then would you explain why I get great signal in a goddamn MALL?

Think about it: if you have 1/4 tank of gas, you have 3/4 tank of air...there is no bladder in any normal gas tank, cap on or off has no bearing.

People get the weirdest ideas in their heads I swear!

hah alright my buddy was wrong. understood. so does anyone have any idea what i should do?


The only hose i really thoroughly checked is from the AFM to throttle body.


Check all hoses for vaccum leak?
Then remove ICV and clean?
If problem is still there, look into ICM needing replacement?