Elantra XD (2001-06) :: P0519 Idle Erratic / RPMs Constantly High

My friend was having trouble with her 2001 elantra. Her idle was erratic and her RPMs were constantly high. we checked every where for a vacuum leak but could not find one in any of the lines. We went on to switch out the idle air control valve, the throttle position sensor, and even cleaned out her throttle body. we threw up our hands and sent it to a shop. Come to find out there WAS a vacuum leak. apparently in the air idle control valve sensor there is a gasket that seemed to be missing. I of course didn't think about replacing a gasket when I replaced the sensor because I never saw one there.

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Ford F-150 - 1997-2003 :: 1999 - Service Engine Soon Light On Sometimes At High Rpm Or Rough Erratic Idle

My trucks symptoms include a illuminated service engine soon light, sometimes a high rpm idle, and sometimes a rough erratic idle. When a scan was done it indicated the oxygen sensor was defective. The issue is: which specific one (there are multiple oxygen sensors) or how could I check or determine the faulty one for sure. I am trying to economize and replace only the bad one myself if possible. I own a good multimeter, can it determine the bad one? 1999 F-150 4.2 Litre V6 oxygen sensor dillemna....

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Tiguan :: Erratic Idle With AC On

At my wits end with a Tiguan problem that my dealership seems to be clueless ....

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Grand AM :: 1999 / 3.4 - Erratic Idle On Start-up

Starts rough but clears up after about a minute, I'm assuming the IAC is sticking. Whats the proper procedure for disconnecting and removing the cleaning and re-installing?

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Santa Fe (CM - 2007-12) :: Engine Light And Erratic Idle

My wife was complaining of the ESC light came on and off. Rough idle. Also has a check engine lite.

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Ford - Mustang :: 1994 - Erratic Idle And Stalling

I have a 94 Cobra Mustang with a 5.0. For the past few months it has had an erratic Idle and stalls when trying to idle. I've had a number of suggestions on how to fix it and nothings seems to work. I checked for vacuum leaks, changed PCV, new plugs, new IAC valve, tested ICM and throttle TPS and even adjusted idle. Still no luck.

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Touareg :: Engine Light Came - Idle Erratic After Car Started?

I know its a shot in the dark but my engine light came on the other night. Its a 07 v8 with 25k mileage. i started it up idled fine for 30 secs, then the idle started to get erratic up and own for 15 secs leveled off and the car ran fine. I drove for 10 minutes turned the car off for a couple of hours came ack started her up and engine light came on no rough idle or anything.

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Ford - Explorersport :: 1999 - Erratic RPMs When Idle And Rev When Braking

Here is a YouTube video showing my erratic RPMs while idling in park, then pressing and releasing the brakes and gas to show what happens each time: [URL] ....

I just bought a 99 Explorer Sport. The history I know is that the truck has 200k+ miles on it, with the engine replaced. Replacement engine has 90k on it.

Was told the fuel pump, and serpentine belt (I think, he said "main belt") were replaced in the last few months.

The car was driving fine on the test drive and for the first few days of owning it. Then a clicking sound started form under the hood while driving.

I first noted the clicking while at a red light, and when I accelerated it stopped. Over the last week it has increased in frequency every day and now is almost constant.

This evening I was coming to a stop with my foot off the gas and when I hit the brakes the RPM went up, and car lurched forward before stopping gently. This kept happening so I drove home and took the above video. Video taken shows the RPMs jumping up when in park and going form idle to idle with brake depressed. when I rev the gas and let go, the RPMs fall, hang for a couple seconds, and then fall back to ~1000. The captions are very accurate, they show exactly when the brake or gas was pressed and when they were let go.

My obvious question would be WHAT IS CAUSING THIS? Also, ARE THE CLICKING AND THE RPMs RELATED? Finally, SHOULD I AVOID DRIVING IT? I need to drive it a few times through the next few days and I can't really avoid it unless it will mean serious damage.

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Santa FE SM (2001-06) :: Erratic Idle - Revs Up And Down From 1200 To 2600 RPM

Daughter's 2001 Santa Fe Delta V-6 2.5 engine, needed lower ball joints. Replaced the entire lower arms as more cost effective & actually a bit less work, for me anyway.

So While under it, see oil dripping down back of engine. Decided to replace valve cover gaskets. So I start to disconnect all the involved connectors, brackets etc to pull the Upper air intake to get to the rear cover.

While moving around, find most of the hoses & vac lines baked brittle and dried out and loose even tho clamped, so I replace all of those, plus the PCV valve., & the upper & lower radiator hoses as well. I only removed the upper 1/2 of the intake. I change out the cover gaskets, reassemble every thing, reconnect all the connectors. I noticed that some of the connectors could apparently be switched to other sensors, but since all the lines seemed so backed solid, they actually retained their positions to go back onto the proper sensors.(at least I hoped so & it seemed that way).

Anyway, every thing back together & tightened up, so I start it up & the idle is at about 3000 to 3400 RPMs. WTF? So I pop the throttle a couple of times by hand and finally it drops down to normal, then just as suddenly, it begins SEARCHING for lack of a better word, and starts racing upto 2600 rpm then drops to 1200 then up again then down again.

No check engine light or other idiot lights on. So I shut it down & check all the connections and hoses, nothing disconnected or left off or loose. I start it again, and it immediately begins running high & low searching for the idle again.

I shut it down again, and put the MacPro scanner on it and NO codes either set or pending. I next check the Haynes Manual I have for it, & the closest thing I can find to my problem says: Engine Lopes while idling or idles erratically 1) Vac leak 2) Leaking EGR 3)Air filt clogged 4) Fuel pump not delivering enough fuel 5) Leaking head gasket 6) Timing belt/sprockets worn 7) Camshaft lobes worn

By process of elimination, not #'s 2) According to service manual, there is no EGR valve on the 2.7, and I couldn't find one either, #3) Air Filter is new & clean, #4) ran fine before I worked on it & with the engine revving up to 34 or 3600 rpms, getting plenty of fuel, #5) Have had many head gasket problems over the years on many vehicles, never anything like this, and again, it ran fine until I worked on it #6 & 7) Doesn't seem to me to be a belt sprocket or cam shaft problem, as none of that was touched & again, it ran fine until I worked on it. This kind of narrows it down to #1, for me, but this is not like any vacuum leak I have ever come across in 45 years of auto repair. I have found & fixed many stumbling idles due to minor leaks but never had anything like this.

I next called a friend who owned an automotive machine shop & who I used to do work for, and now runs a highway dept garage for a municipality who has been a certified mechanic for many years, told him all the above & the only thing he could come up with was a MAJOR vacuum leak, like possibly the upper plenum gasket rolled up or got torn some how when I replaced the plenum and he suggested that I try a smoke test.

Scratching my head, I go back to the car, & break out my home made smoke machine that I use to successfully pinpoint leaks in emissions systems. I ran it for quite awhile, and found some light smoke leaking from somewhere down around the head, but due to the construction of the engine & no way to get the light to shine under the plenum, could only guess that he may have been right & that there may be a large leak down at the lower intake manifold to head gasket. Needless to say, I removed the upper plenum again, & this time also the manifold to heads, and the gaskets looked like they may possibly have leaked slightly between the ports, & quite possibly somewhere around the number 6 cylinder. So I cleaned the surfaces & am putting on the new gaskets that came in the set with the upper plenum to manifold gasket set.

My questions after relating all of this:

1) The 2 gaskets between the manifold & the cylinder heads have a blue stripe around all 3 cylinder port holes (appears to be some kind of sealant or factory applied silicone bead) & there are no markings of any kind anywhere on the gaskets, so do the blue stripes face DOWN to the heads or UP to the bottom of the intake manifold ?

2) Regardless of which way these stripes face, should I use any kind of high temp sealant around the port holes in addition to the gaskets, or just install them dry ?

3) Can the Idle Air Control on the Throttle Body Fail & affect the idle like the problem I am having, but NOT set a computer code ?

4) Can the Throttle Position Sensor affect the idle like this and NOT set a computer code?

5) I also found an electronic valve between the Air Intake & firewall, it is labeled PCV and has an OEM part number after that, I believe this to be the Purge Control Valve, which connects the TB to a plastic line which I believe runs down to the emissions canister under the vehicles front seats. Am I correct in thinking that even if this part had failed, it would have NOTHING to do with my erratic Idle problem, but would throw an emissions computer code?

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Elantra XD (2001-06) :: 2002 - Erratic Idle And Ran Rough At 1200 Rpm

I just picked up an 02 Hyundai elantra manual trans that needed a transmission. ran fine before I replaced transmission but after putting it all back together the car now how has an erratic idle. it will rev from 2-4000 rpms. I tried spraying for vacuum leaks idle didn't pick up any higher. replaced tps and iac and didn't make a difference. the only thing that did make any difference is unplugging map sensor. dropped idle to about 1200 rpm but ran rough. could this affect the idle.

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Ford F-150 - 1997-2003 :: Erratic Idle When Get Off The Freeway And Stop

I have an 01 f150 4.6 4x4 automatic with 90,000 miles. I have an erratic idle but it only happens when I am on the freeway well actually when I get off the freeway and stop. the idle will fluctuate between 750and then drop to 400 then back and forth til I get moving again. I replaced the IACV because it was doing the weird humming and vibrating the intake tube. The humming is gone but still idles funny as stated above.

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Passat (B7) :: Hard To Shift Into First Gear After Coming To A Complete Stop When Raining

I got new brakes pu ton lats month (semi-metalic). Any way I was driving to work and it was raining , roads were wet and my car was shifting weird after coming to a complete stop. once i went it would shift into first gear hard. I took it to a mechanic but he couldn't find a problem.

Then it was fine, no problem but today it was raining an dmy car did the same thing. Anytime I went when a light turned green or his the gas after being at a stop sign. the car would stutter as it shifted into first gear. like it would go , then act like it was stuck and then shift

It has only happened twice and its both been raining. Also my tires are really really bad.

Could it be the tires aren't gripping the road and that's why my cars shifting funny, like the tires aren't caught up?

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Passat (B7) :: 1.8T - High Idle On Startup

Even on a warm day, when I "cold start" the car....the revs hang high for a long time....at least a good minute or two. This is my first PZEV(VW) engine though--CPRA--so I'm assuming it's for the emissions? With the intake & exhaust I have on...it's obviously A LOT more noticable.

For the first 10-15 seconds, there is a HUGE sucking sound for the SAI pump and then that shuts off....but then it still screams along at 1,200-1,500 RPM's for another minute or two until it'll FINALLY settle down to idle.

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Prius (2004-09) :: Check Engine Light Code - Erratic Idle

It came on 2 months ago, took it to dealer, code said "erratic idle", it idled fine, smooth as it always has been, dealer turned of lite, said let him know if it comes on again.

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Ford - Explorer :: 2008 V6 - Erratic / Jumping Idle While At Higher RPMs

My wifes 2008 Eddie Bauer Explorer V-6 recently started having an erratic idle and we've started noticing it while at higher RPM's. Its almost as if there is a cylinder that misfires but no engine light is coming on. The car stumbles like it is going to start to die, then the idle jumps up and smooths out. A little while later it does the same thing. The car has I think 74,000 miles on it and has never had the plugs or wires changed. I change out the fuel filter roughly every 24,000 miles and did it recently in the spring. Any places where I should start looking? Could a misfire not trigger the check engine light?

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Accord :: 98 / 2.3L - Erratic Idle Speeds / Engine Can Barely Stay Running When Warm Up

98 Honda Accord with 2.3L has 354,000 miles on it and up until recently ran like it was still new. Have developed erratic idle speeds. When it is cold it idles around 1100-1200 rpm. When the radiator fans are on or the A/C compressor is on it runs around 800-900 rpm. These are normal speeds and great. However, when the engine is warm/hot, in PARK, radiator fans are off, and A/C compressor kicks off, the idle speed drops to what appears to be about a rough idling 500 rpm's and the engine can barely stay running. I've attempted to look for the obvious. I own the Honda Shop Service manual if there is a particular component or most likely suspect area I should start at.

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Ford Aerostar :: Erratic Idle - Air / Fuel Ratio Is Too Lean Or Rich For PCM To Correct

97 shortie. 3.0 245,000 miles. I've already cleaned the throttle body and the idle air control valve. Throttle position sensor reads 5 volts, good ground, and a smooth voltage increase from idle to wide open throttle and back down. Which of these codes is most likely to cause erratic idle? Mostly in the morning.

P0340 Camshaft position sensor.
P1443 Evaporative purge flow sensor.
P0401 Insufficient EGR flow.
P0171 Air/fuel ratio is too lean or rich for PCM to correct.

I doubt it's number 1, and number 4 seems too general to be any use. I'm leaning toward number 3. Seems I read somewhere that the tube from the exhaust gets plugged up. This started when I disconnected a plug from the blue air bag box to get rid of that beeping. Coincidence?

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Passat (B6) :: High And Bouncing Idle In Neutral

Came to a stop at a loooooooong light the other afternoon. I popped the AT into neutral, and the engine idle rose to around 2000 RPM, dropped to about 1500, then started cycling in that range. CEL also showed up.

Now, whenever the transmission is in either P or N, if I blip the throttle to bring the RPMs into that range (1500-2000), it stays in that range and cycles up to 2000, drops to 1500, wash, rinse, repeat. Blipping the throttle above 2000 does not change this behavior... as soon as the RPMs drop back to 1500, zoom it goes, right back to 2000.

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Passat (B6) :: High Idle Speed At Odd Times

I bought my 3.6 in november with 2k miles on and now have 15k, in the last month or 2 I've noticed that at odd times it idles high. It normally idles at 500-600 id say and will randomly peak to 1000-1100. It wouldn't really bother me except it sounds like hell and I have to practically stand on the brakes for it not to jump forward. I've had 13k miles and 6 months of problem free driving

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