I recently learned that an Echo owned by a friend of my wife has the same issue that is occuring in a small percentage of Corolla, Matrix, and Vibe cars, all of which share the same 1800 cc engine.
I have initiated 5 similar threads on forums located at 4 different websites and since February 2005, much ink has flowed.
I am interested in knowing if there are other post 2002 Echo (Yaris) owners who have an identical problem.
If you do, then you will be noting that during the 2nd minute following a cold startup (car untouched for at least 6 hours), your idle rpms jump up and down by several hundred rpms creating a pulsing sound that lasts no more than another minute (5 to 30 pulses depending on temperature), afterwhich, the car will behave perfectly until the following morning. This makes a diagnosis at the dealership very difficult.
This issue rarely occurs when the temperature is above 32 degrees F (zero celcius).
Most if not all reports have come from owners of manual transmissions.
Feel free to post your comments and if there is as strong a response with Echo cars as there is with other platforms, then I will introduce a poll question for Echo owners.
I have an 06 Yaris which does that - although in my case it idles nicely at about 600 then drops a couple of hundred and shakes, then goes back up. It cycles through this every 10 seconds or so. It does it when the car has hit operating temp but not super hot. It seem to go away if I drive for more than half an hour or an hour. And yes, I have a manual transmission. A similar post on another thread had a reply from one or two people who had grounded their engine compartment better than stock and that seems to have cured this issue.
Mine does it under a specific condition only. Start cold car after sitting overnight. Pull onto street accelerate slowly as one should when the blue light is on and step on clutch under braking for a light or stop sign. The engine will hunt 2-3 times or until the car comes to a full and complete stop, but only hunts upward from steady idle. Once the car stops, the idle sets and is fine until the next stop light I always hit, and then I don't see it again till the next day. The idle has never come under normal 600-750 reported per the tach while it does it, so no shaking or other downsides happen. Just a smooth speed up to 1100 rpm and down, up and down, stop idle sets low, all normal.
This is perhaps the toughest challenge the car faces: decel, cold fuel/high idle, movement with throttle closed or closing. So many things change under these conditions.
Now, mine doesn't stall, or even think about dropping RPM down, so I have no worries yet. One or 2 idle hunts a day...IMO not worth the trip to the dealer to worry about.
Could be a sensor problem ( engine coolant temp. sensor, intake air temp sensor). Or the idol air control, etc. or even the ECM. However these problems should be detected by the service dept?
Since none of the posts above are exactly similar to my issue, let me provide the following link to the thread in the Matrix forum of Toyotanation and the you will find that the first post there will open the door to other forums thread and the actual sound recording.
When I see several postings in this thread claiming to have the identical noise under the identical conditions, then I will set up a new poll thread here.
Please do not vote in the Matrix/Vibe polls on the other threads. Save your vote for this Echo/Yaris forum.
I have an 06 Yaris which does that - although in my case it idles nicely at about 600 then drops a couple of hundred and shakes, then goes back up. It cycles through this every 10 seconds or so. It does it when the car has hit operating temp but not super hot. It seem to go away if I drive for more than half an hour or an hour. And yes, I have a manual transmission. A similar post on another thread had a reply from one or two people who had grounded their engine compartment better than stock and that seems to have cured this issue.
Mine does it under a specific condition only. Start cold car after sitting overnight. Pull onto street accelerate slowly as one should when the blue light is on and step on clutch under braking for a light or stop sign. The engine will hunt 2-3 times or until the car comes to a full and complete stop, but only hunts upward from steady idle. Once the car stops, the idle sets and is fine until the next stop light I always hit, and then I don't see it again till the next day. The idle has never come under normal 600-750 reported per the tach while it does it, so no shaking or other downsides happen. Just a smooth speed up to 1100 rpm and down, up and down, stop idle sets low, all normal.
This is perhaps the toughest challenge the car faces: decel, cold fuel/high idle, movement with throttle closed or closing. So many things change under these conditions.
Now, mine doesn't stall, or even think about dropping RPM down, so I have no worries yet. One or 2 idle hunts a day...IMO not worth the trip to the dealer to worry about.
Your issue sounds closer to mine.
Try starting the car in the morning after a cold sit overnight (below freezing) outside and leave it in neutral (clutch out) for 4 minutes while it warms up. You may find like me that there is a window (second minute following a startup) when you get 3 to 30 pulses depending on the temperature. Four minutes is a long time so use your stop watch.
Your pulsing seems to be between 1100 down to 750. It usually takes 5 minutes when cold for a typical motor to lower down to 750 rpms. Mine never goes under 1800 until 4 minutes have passed.
My car won't repeat unless it sits still for 6 to 8 hours in the cold.
Let us know your new observations and the year, model, and transmission type of your car.
Could be a sensor problem ( engine coolant temp. sensor, intake air temp sensor). Or the idol air control, etc. or even the ECM. However these problems should be detected by the service dept?
According to the other forums, the best mechanics accross the continent replacing a variety of parts have yet to produce a documented solution.
Toyota Canada has agreed to let their engineering team in Japan look for a solution.
I am more interested at this time in gathering statistics than in looking for an elusive solution, as my dealer has already spent 5 hours of warranty time unsuccessfully.
I don't expect a solution to what I perceive as a complex engine computer control problem, so all I want to do is access the potential loss when I resell my car in 4 years from now, due to the disclosure that I will have to make about the car's history, even if the issue is strictly cosmetic.
I foresee myself losing about 2000$ on a resale. $2000 is the amount that the dealer would offer me less in a trade than if I could find a private buyer.
To be compensated from the manufacturer in this event, I will be able to prove that the problem existed before my warranty expired and that the internet forum(s) results show that most, if not all, people do not want a car that makes this noise even if this noise is purely cosmetic.
It may be less expensive for the manufacturer to pay off a handful of owners like me than to spends millions of dollars having a modified engine computer re-certified by the EPA.
The next generation of cars may not have this same issue.
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