Why does idle speed surge?

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Recently, I started having a bad idle problem where my idle would go up and ... to a complete stop the rpms start going up and the car accelerates on its own. ...... I thought hey wtf I'm going to research this
grey seal on my throttle body.

Idling Stop System - Honda

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Honda Motor CompanySave fuel just by driving normally,with Honda's Idling Stop System ... Normally, once you start an engine, it continues to consume fuel until you switch it off.

THE END OF ALL Idle Surge - Bounce - etc Problems Thread - Honda ...

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May 9, 2007 - To fix your super ghey idle problems: 1) Take a very good look at your intake ... 4) If that didn't fix the bounce, try unplugging the IACV, if that stops the .... I have a friend thats going through this problem right now in his h22 accord. .... mgags7:I'm can't seem to email you in regards to some of the parts you ...

Engine stalls cold or RPM fluctuates at idle up and down or dies near idle.

This problem is commonly caused by a dirty automatic idle speed control valve and throttle valve but always run a OBD2 fault code as well as the cleaning procedure. Buy a can of throttle valve cleaner (do not use carburetor spray cleaner!) from NAPA or Carquest (made by CRC chemicals) and spray it into the air intake while the engine is running, use up about 1/2 the can, engine will try to stall hold the speed up, shut it down and let it soak for 30 minutes, restart and blow out the remaining fluid, shut it down and disconnect the negative battery cable for 5 Min's to reset the base idle control. If the above cleaning doesn't cure your issues you need to have the computer controlled automatic idle speed control system diagnosed and repaired by a dealer or electronic engine control repair shop.

Without knowing what car it is ...make. model and year this is a very vague question. A quick and dirty educated guess sounds like your timing has jumped ... if it's a timing belt, open the cover and check the timing marks ... or if it runs put on a timing light and look where the timing is ... sounds like it's firing after top dead center.

Most trucks and car will idel about 1500 to 2000 rpm until they. Are warmed up. Its a warm up feature

1.Verify that the cooling system is full of coolant and there is no air in it. 2. Remove the air boot from the throttle body and cover the throttle body with something that will stop the airflow . the Fast Idle Valve is the problem.

The idle adjustment screw in throttle body has carbon build up on its tip.need to remove screw clean depoisits off tip,carbon in idlescrew port(with carb clean) re-install idle screw,seat it,then back out 1 1/2 turns.start car and hold at higher idle to blow out carb. clean &deposits out of throttle body then recheck for surging once warmed up.

Something is riching or leaning this vehicle out at the wrong time. I'm gonna go with ERG valve being stuck in the open position. The only time this thing should work is at crusing speeds. Once the car has cooled down the fast idel cam takes over and prevent it from stalling. Once temp is within range idle cam stops and EGR is dumping into the mixture.
Use shop manual to do proper testing for the valve( probably a hand held vacuum pump is all you will need and gum out to free it up but you should properly replace it if it turns out to be the culprit.

The 1st thing to do here is test the engine control computer for fault codes, if none are present then do the following to clean the automatic idle speed control valve and the throttle valve, they get sludged up and this causes stalling and idle surge among other issues. So before you do any parts replacing do the cleaning, it costs about $5 and 30 minutes of your time. Here is the procedure. My experience? 35 years as a dealer factory trained technican.

Buy a can of throttle valve cleaner (it is made by CRC) from the local auto parts store, spray it into the air intake through the throttle body of the engine until you have used about half the can, you will need to hold the idle up while you do this, it will try to stall, after this shut the engine down and disconnect the Negative (-) battery cable for 5 minutes. The intake is now clean, if you continue to have the idle speed control problems you may need to seek the help of a professional.

check the i.a.c. (idle air control) valve near the throttle body, it fixed my low idle!

check your high idle valve may need to be replaced.situated at the side of throttle body.

good luck
cyril