I had something strange happen yesterday.
I got into my car after work and started the engine.
While I was belting up and putting on my sunglasses the engine started to act funny.
Shifter was in “N” and the clutch pedal was out.

All of a sudden the RPM’s started increasing up to about 2,500 and held a few seconds and then went back down to idle.
It did this several times while I sat there dumbfounded.
At first I thought the floormat may have come off the pin and moved up onto the gas pedal. Checked that and it was OK.
I let it do this about 5-6 times before I turned the car off and let it sit for a minute or two.
I started it back up and it was still doing it.
I “blipped” the gas several times to about 3,000 RPM and it returned to idle and kept surging.
When it decreased, it sputtered and almost sounded like it was going to stall.

I had an appointment to get to so I said the hell with it and pulled out onto the road.
So I’m on the highway and I could feel it surging and in-between shifts it was holding the RPM’s instead of dropping.
After about 10-Miles I got off the highway and pulled into the parking lot and it was back to normal.
It ran normal on the way home and it ran normal this morning.

Any ideas?

Bad gas?
Dirty CAI filter? (it is)
Dirty fuel filter?
Possessed car?

The car is due for its 30K service, but not until probably the end of May. I’m at about 28,500 right now.
I’ll have them look at it then, but I wonder if you guys have any ideas if it happens again.
Or are they gonna try and blame my CAI?

 

2500 RPM!!!

never seen it go that high..

Air intake Control valve is my guess.... the ECU is searching for idle postion when it jumps like that.

 

Could a dirty K&N filter cause or aggravate this problem?
I usually clean and oil it once in the spring and once in the fall.
I never got around to it last fall so a cleaning is overdue.

 

 

Not 100% sure.. is it pretty dirty and clogged up?

the reason why the ECU searches is either the battery was disconnected and the ECU is relearning the idle position or the car is not getting enough static air at idle.
Most of the S/C'ed guys needed to adjust the set screw to let more air in during idle.

 

I'm gonna say IAC valve. Similar thing happened to me, dealer replaced under warranty.

 

IAC before I even read the thread.

 

Definitely IACV. Honda IACV uses thermo-wax. That's why it went away after driving for a while, because the engine was warmed up.

Get it checked out.

 

maybe the tps, throttle position sensor

 

I had a simlar thing happen last night. I was driving all over the place, Some traffic, some HW speeds from 0-100, engine shut off & back on for like 2 hours. I just got off the HW onto a local road & stopped at a light. I wathed my RPM's hover at like 1500 even though I was stopped in N, then it went down slowly. I blipped the gas & again it hovered at 1500. Then the light changed I went & it didn't do it again...strange?? My IAC valve was changed last summer. The air filter looks ok. I swapped in the K&N into the Icebox. Only been on for about 5K miles.

 

For the record, my car hasn’t done this since the day I started this thread over a week ago.
I still haven’t cleaned my CAI filter, but it’s on my list of things to do.

Mileage is currently at about 29,200 miles, so I’ll probably be scheduling my 30K service for sometime in May.
I’ll have them look into it.

 

Most likely the IAC as others have said. It'll come and go. You might roll up to a stop sign one day and have the car stall.


Too much oil during the K&N cleaning/oiling process can clog/damage the IAC or it could just need adjusting.

 

Last time I cleaned & oiled it was about this time last year.

 

I'm not saying that's the root of your problem this time. Just a friendly FYI

All the symptoms lead to an IAC valve though.

 

Iacv

 

Where is this set screw cuz I think I need to adjust it. Also, how do you know its adjusted right. I am so confused about this. Cuz my rpm keeps oscillating(sp?) between 100-1,000 rpm during idle.
When I turn the car it jumps to 2k rpm and drops all the way down sometimes the car even dies if I dont give it a little gas.
While driving if I come to complete stop or press in clutch to slow down the car dies. I am so disappointed I dont know whats going on.

 

The same exact thing happen to me about 2months ago... But i have a stock '02 type s... I let the car sit for about 24hours cause i didnt want to drive it when it was doing that... so i left it at my house and then i started it up about 24hours later and it was completly fine... i didnt understand that at all but i still had brought it into the Acura dealership and had them check it out and they said there was nothing wrong with my car and they said that it might have just been bad gas...

 

It happened to me before and like you Shawn, it hasn't happened since.

 

When do gas stations switch from the winter formulated gas to the "normal" gas? I know last yr, my car had a hard time starting around early spring. When I took it to the dealer, they said it is somewhat normal when they switch the gas formulations. Shawn, maybe it was your car adjusting to the gas????

 

Where exactly is the IACV located ???
Is it up on the throttle body or would they need to disturb my CAI pipe to replace it?

I don’t want the dealer giving me shit about the non-OEM intake.

 

It's located underneath the throttle body.

 

UPDATE.....

I had my 30,000 Mile service done today and I mentioned this problem and described it in detail.
It hasn’t done it since I posted this.

Their analyses:
“Could not duplicate customer’s noted problem”… No repair made.

Oh well…at least it’s on record if there is a future problem.

 

Oh well... I'm sure it will come back again at some point.