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HELP! high idle intermittent... did search and it still happens

2003 Views 3 Replies 3 Participants Last post by  imprint
hi all,
Just wanna say in advance, sorry for the lengthy post and THANKS for any help. I need some help on this problem. I have an 03 Ody with approx. 104,415 k miles. I noticed this problem occurring only AFTER I had my 100k service done includ. timing belt, water pump, cabin filter, drive belts, thermostat, and various seals. I did multiple searches and found multiple threads saying that it could be the IAC valve, EGR valve, power steering switch behind the right front tire, vacuum leak. etc.

-no CEL or TCS lights on
-only when the van is hot (driving for about 45mins - 1hr) I get a high idle around 1000 - 1500 rpms in stop and go traffic, city driving. Then at times it goes away on its own... intermittent.
-its a pain when its heavy traffic cause Im constantly on the brakes cause the van wants to take off on its own or im pressing the brakes harder then usual.
-slowing down and just before coming to a complete stop, rpms spike to about 1200 and the van lunges forward, then rmps settle to 1000.
-when rpms are high (1500-1800) and im parking, when I turn off the engine, it sounds really really rough when its shutting down.
-when Im accelerating and lay off the gas (no braking) I notice the rpms drop dramatically and spike back up then slowly decline. (is that normal?)

non symtoms...
-the needle isnt "hunting" up and down rhythmically
-no signs of engine threatening to stall at stop lights or parking lots

Things Ive done so far...

1st time around (worked for about a week then the symptoms came back)
-cleaned the IAC valve with sea foam and qtips and used new oem gasket (when taking apart I noticed that its magnetic in the black electrical box, does it matter what position the flat platform thats on the butterfly is in when putting the electrical part back on?)
-cleaned EGR valve with new gasket.
-poked or probed the PS wire switch with a stick to see if it made the idle respond (turned out ok)
-cleaned under my valve cover (passages were covered in carbon build up: test drove but it seemed like I lost power)
-air dried with a compressor

2nd time around (again, worked for about a week then the symptoms came back)
-cleaned the IAC valve (this time I used carb + choke cleaner) also, I was able to get the butterfly to rotate a complete 360* both ways. The first time, I felt restriction rotating it so I stopped and rotated the other way then stopped. I had restriction under the "bridge" or that part that I cant get to.
-cleaned EGR valve with carb + choke cleaner
-both air dried with a compressor

3rd time around (worked for a few days)
-checked for broken or frayed wires on the PS switch (none)
-cleaned with electrical contact cleaner
-used di electric grease

a few questions...
-when clean, if my IAC valve is bad, would I still get the same intermittent symptoms or would it be more severe and constant?
-when clean, if my EGR valve is bad, would I still get the same intermittent symptoms or would it be more severe and constant?

Id just hate to spend a few hundred of dollars to do process of elimination when none of them are the problem.

Thanks again for any help, info, advice on this troubling problem that just wont leave me alone.
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· Registered
35 Posts
Discussion Starter · #2 ·
just to clarify...
the flat platform is circled in red... does it matter if its on the top, bottom, left, right: when inserting it back in the electrical connector?

and where I was getting resistance when cleaning the 1st time (bridge) is circled in red.
Auto part

· Registered
12 Posts
A similar problem happened to me after the timing belt?valve adjustment 100k service. 2002 EXL with 104,000 miles. Surging idle speed constantly. The dealer said the computer needed to relearn or something.
Took it back to the same dealer again and they changed the IAC valve I believe for $400.
It was still doing it although reduced. I took it in to a different dealer for another problem and mentioned the surging. They saw it happening when I drove in.
They came back and said the vacuum lines were hooked up wrong and didn't charge me to fix it. I complained to the original dealer and they refunded the full $400 repair cost.

· Registered
5 Posts
I've had the same problem on my 02 EX (@ about 96,000km) for a couple of years now. The first time it happened was shortly after a transmission change on the first very hot day we had in June. The engine rpm spiked to over 3000rpm. I just shut it down immediately, nervously waited about five minutes, then started it up again an the rpm immediately shot back up to just under 3000rpm. I quickly shut it down again and called a tow truck.
The tow truck took me to my local Honda Dealer, which was about 10 minutes down the highway. When we got to the dealership and after going through all the check in procedure; the service rep asked me to start it up and I guess it had cooled down enough because it ran perfectly normal. I left it with them for the day so they could try to replicate the situation, but, they could only get it to rev up to about 1200 to 1500 rpm.
Since it was not tripping any code they couldn't come up with a solution for me.
They have checked with Honda and other Honda dealers to see if they could offer any input, but, so far nothing. They say they don't want to just randomly start throwing parts at it until they have something to go on, and I certainly appreciate that.
So, for the past two years I have just been managing the situation. When it starts to rev up I find a spot to shut it down and let it cool.
The dealership has been very good and we've kept in contact about this issue, but it's getting frustrating.
SO, if any one has any input or solutions to this problem, I would love to hear them!!
Many Thanks in advance!!
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