RPM fluctuation.....

[strat61caster]

Originally Posted by radroach

I'm trying to figure out if I have an issue. Idle drops to 600 rpm, makes it harder to get a quick, smooth start.

The vehicle idles at around 650-750 rpms to save fuel, this is standard. On most cars you usually have to give it a little gas to get going.

[davidsolarbell]

My Car Absolutely does this. It gets bad too sometimes. One day it completely idled out 15 times in a row, many times at stops. It just bounces around and then gets too low and shuts the car off. It is very Frustrating. Do we have a fix yet?

[TanMan]

Originally Posted by davidsolarbell

My Car Absolutely does this. It gets bad too sometimes. One day it completely idled out 15 times in a row, many times at stops. It just bounces around and then gets too low and shuts the car off. It is very Frustrating. Do we have a fix yet?

Geez, it's been a year already and Toyota / Subaru still haven't got this problem
figured out!?

[mnsayer]

Temperatures are getting extreamly hot where I live 113F and getting hotter, and what do you know when I stopped my car yesterday the RPM dropped sharply. The last time i had this issue was last september.

[Mr.EvoMR]

So is there a fix?

[Specialized86]

Mine does this as well. Is it the radiator fans kicking in?

[strat61caster]

Originally Posted by Mr.EvoMR

So is there a fix?

What is there to fix? All evidence points to 'this is normal' and is probably a consequence of running the idle as low as possible to get the best fuel economy. Annoying and sketchy but shouldn't be a problem unless the engine stalls.

Edit: Some aftermarket tunes raise the idle up to 750-850 and report that the fluctuation goes away, may be an option if you're planning on messing with that anyway.

[Mr.EvoMR]

Originally Posted by strat61caster

What is there to fix? All evidence points to 'this is normal' and is probably a consequence of running the idle as low as possible to get the best fuel economy. Annoying and sketchy but shouldn't be a problem unless the engine stalls.

Edit: Some aftermarket tunes raise the idle up to 750-850 and report that the fluctuation goes away, may be an option if you're planning on messing with that anyway.

No way its normal when the CEL turns on after it idle's.

[strat61caster]

Originally Posted by Mr.EvoMR

No way its normal when the CEL turns on after it idle's.

That seems to be different issue than the topic you've posted in.

That should fall under dealership warranty work, do you have the code for the CEL? You'll get a more concise answer if you can share the code the ECU is producing.

Idle fluctuation on it's own doesn't seem to be a 'problem'.

[jonvaldeeeezy]

perhaps something is wrong with the pedal? idk just adding my 2 cents to the think tank

[Fepat55]

I have also encountered this . Stopping at a light the rpm will drop to 500 rpm and then immediately rev to 900 and then cycle down and up a few times before settling at 650. It has not stalled on me yet. I also note that this does not occur when the weather is below freezing.

[Young_makaveli]

Hey did anyone notice that when you are stopped at a light and If you press the brake pedal in and out that it would make the rpm fluctuate no matter what.

Example : you are stopped at your driveway with the handbrake up, then you press the brake pedal all the way and suddenly the rpm would fluctuate and when you release the pedal it goes back to 600-700 rpm and when you press again it would fluctuate again and so on .

Lemme know what you guys think

Thanks

Sent from my SM-N900W8 using Tapatalk

[strat61caster]

Originally Posted by Young_makaveli

Hey did anyone notice that when you are stopped at a light and If you press the brake pedal in and out that it would make the rpm fluctuate no matter what.

Example : you are stopped at your driveway with the handbrake up, then you press the brake pedal all the way and suddenly the rpm would fluctuate and when you release the pedal it goes back to 600-700 rpm and when you press again it would fluctuate again and so on .

Lemme know what you guys think

Thanks

Sent from my SM-N900W8 using Tapatalk

Power brakes utilize a vacuum from the engine to aid operation. By pumping the pedal you deplete the vacuum and draw it from the engine intake which may cause idle fluctuations. I made a similar observation but couldn't repeat it when the engine was at temperature while the idle hunting did repeat.

http://en.wikipedia.org/wiki/Vacuum_servo#Brake_booster

[Young_makaveli]

Originally Posted by strat61caster

Power brakes utilize a vacuum from the engine to aid operation. By pumping the pedal you deplete the vacuum and draw it from the engine intake which may cause idle fluctuations. I made a similar observation but couldn't repeat it when the engine was at temperature while the idle hunting did repeat.

http://en.wikipedia.org/wiki/Vacuum_servo#Brake_booster

Thanks a lot man

Glad to know it's not a issue

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