try and clean the MAF sensor for one, also you can do a little test to see of your intake manifold gasket is leaking. get some carb cleaner or brake parts cleaner, something flammable and in an aerosol can, and spray it all around where the intake manifold meets the cylinder head, if the idle suddenly gets better then you most likely have a leaking gasket.

what likely happened was that your MAF was reading slightly off or your intake manifold gasket was leaking but the ECU had adjusted fuel trims to make up for it so it would run fine, that is up until the battery went dead and the ECU "forgot" the fuel trims and now has a rough idle.


good luck.

 

Thanks TrdSpeed 140. I will try what you recommend (it makes perfect sense) and update the board as soon as I can. The more reading I do on the Corolla the more I find out about problems with dirty or bad MAF's.

I guess it could be worse.

 

yea, the intake manifold gasket has also been discussed a bit on the forums as well

 

I changed my battery about an hour ago and I have the exact same thing happening. It idles for crap but runs good once you get going. I keep coming accross something where the computer has to "relearn" your driving habits. I'll give it a few days before I take it to the dealer. If you do find anything out, please post it and I'll do the same. I really doubt a host of sensors went bad because I changed the battery.

 

I have an appointment on Monday with the dealer so hopefully (fingers crossed), I'll have a resolution to this sometime soon.

I'm actually hoping it's something minor (bad intake manifold gasket) because if this is limited to some sort of "relearn" procedure...let's just say I've purchased my last Toyota.

I'll post the outcome next week. Thanks and good luck.

 

subscribing to this because I need a new batt soon. Was your car included in the ECM recall?

 

Nope. The recall was for 2005-2008 Corolla/Matrix owners.

 

Well, I don't know what I did but it's all better now. I drove it around a bit and the stalling went away. Now it runs like it did before...only starts better. Hope you get your vehicle issue resolved.

 

Glad to hear it devin! :thumbsup:

I'm pretty sure my problem is something other than the battery switch. TrdSpeed140's assessment makes sense to me and given that TSB04507 calls for the replacement of the intake manifold gasket (which may cause some rev hunting and rough idle), it leads me to believe that this is a common problem in these cars (and I think this is more than likely my issue).

Will post my answer on the board as soon as I find out.

 

Just an update - I had the car at the dealer for 3-days. They tested everything which included upating the ECM and looking for leaks. They also cleaned out the throttle body and connected the car to their computer (which apparently lets them look deeper into the ECM then a standard mechanic's scanner). The car was tested under load conditions and non-load conditons as well as local driving and highway driving.

The results?

The dealership acknowledges that the rpm's at idle are somewhat low but still fall within the toyota corolla spec limits. They are a little perplexed as to what the problem might be and don't want to swap out pieces blindly without fully identifying the nature of the problem.

My result?

The car is somewhat better but it's still noticible. I suppose I'll drive it as is for now and monitor it.

I'm a little disappointed at the quality of the car. However, the service manager was great though - he even conceded that [in his opinion], corolla engines now have a tendency to get rougher with age but that it usually occurs somewhere in the 60,000 mile range and not at 39,000.

Hope this info helps those who have a similar problem.

 

Just an update - I had the car at the dealer for 3-days. They tested everything which included upating the ECM and looking for leaks. They also cleaned out the throttle body and connected the car to their computer (which apparently lets them look deeper into the ECM then a standard mechanic's scanner). The car was tested under load conditions and non-load conditons as well as local driving and highway driving.

The results?

The dealership acknowledges that the rpm's at idle are somewhat low but still fall within the toyota corolla spec limits. They are a little perplexed as to what the problem might be and don't want to swap out pieces blindly without fully identifying the nature of the problem.

My result?

The car is somewhat better but it's still noticible. I suppose I'll drive it as is for now and monitor it.

I'm a little disappointed at the quality of the car. However, the service manager was great though - he even conceded that [in his opinion], corolla engines now have a tendency to get rougher with age but that it usually occurs somewhere in the 60,000 mile range and not at 39,000.

Hope this info helps those who have a similar problem.

My 2004 Sienna did the exact same thing when I changed my battery yesterday. It's done same thing in the past when changing batteries. Idles like it's going to conk out at red lights but drives ok. Over time it usually resolves on its own but I don't know why it does this. Maybe I change the battery wrong? Does it matter which terminal is placed off or on first? It has done this every battery change since new. Looking for answers. Thanks.

 

that dealership sounds like it has some pretty good techs, they're actually trying to diagnose it instead of just throwing parts/money (your money) at it like some do.

 

well i dont think were going to get any answers from Toyota they dont seem to know what causes the low idle mine did started after a full service and plug change so idd say my battery would have been disconnected for a while as well so maybe it could be the ECM acting up and not been pick up by diagnostics.has any one on here ever changed the iacv just wondering and if so did it fix the idle problem low idle that is...

 

Disconnected the batt today on our 2005 Corolla as the CD player was giving the dreaded "Error 3" message. Ended up fixing that problem after significant disassy of the unit and "manual" extraction of the CD's, but upon reconnecting the battery, car is now idling very rough. Disappointing. Drove the car about 45 miles tonight, mostly highway, still rough. Not getting a good feeling about this... Anyone have any updates/insights?

 

Disconnected the batt today on our 2005 Corolla as the CD player was giving the dreaded "Error 3" message. Ended up fixing that problem after significant disassy of the unit and "manual" extraction of the CD's, but upon reconnecting the battery, car is now idling very rough. Disappointing. Drove the car about 45 miles tonight, mostly highway, still rough. Not getting a good feeling about this... Anyone have any updates/insights?

I recently disconnected the battery on our 2006 LE due to some transmission issues. The car did idle rough due to a low idle speed for about a day. The problem has since disappeared. I think, at least sometimes, this is some learning algorithm somewhere starting out from scratch.

 

Yes, that's right on. A number of things get erased when you d/c the battery including long and short term fuel trim memory, and these are the variables that compensate for individual engine issues. Takes a bit to "relearn" these data.

Our car took about 2 days to smooth out again and return to normal, which I'm very thankful for... Wasn't looking forward to dealing with an idle issue.

 

Just an update - I replaced the MAF sensor and confirmed that the intake mainfold gasket wasn't leaking and the problem still persists. Interesting part is that my mechanic told me has since seen two other toyota's come to his shop with the exact same problem! He's leaning towards some kind of problem in the idle air control valve but once again...the cars are showing no codes and he's therefore relucant to start telling his customers that he may have a fix without being completly sure.

In the meantime, the car is drivable (just annoying) and I've begun using BP gas as I'm told this is a cleaner fuel. I also have some EFI tank additives from Toyota which I'll use regularly (although I really doubt it will help).

I may take a cost approach on this and swap out lower cost pieces first (pcv valve, plugs, etc) before getting to really expense parts.

I'm really disappointed with Toyota...

 

Would just like to toss something out for some opinions - I've also noticed a "harder" start in the morning as well as a vibration/rattle in the automatic shift lever under WOT (Wide Open Throttle). If I place the car in neutral and rev the engine I can reproduce the vibration/rattle in the shift lever. Although I don't see a direct connection to the idle issue...my thought is a bad tranny mount might play a contributing factor (albeit the car would vibrate in the body but the idle would still be its same old low idle). What other components might contribute to the new issue(s) and have a connection to the low idle? Torque Convertor perhaps? Should I look at the exhaust components (i.e., manifolds) to see if a break has occurred? (Although the car exhaust has not gotten louder nor do I smell anything).

I'll take the car in as soon as I can so that my mechanic can put it on the lift and we can look at it from below.

Thoughts are welcomed though!

Tks.

 

I'm having a similar issue right now. Yesterday the battery was disconnected and the terminals cleaned as they were corroded. On my way home I noticed the rough idle when I stopped at a stop sign. I had been driving for about 15 minutes at that time so the engine was up to temperature.
This morning I went to start the car and nothing, the battery is dead. I boosted it and it started and idled fine. I got a minute up the road and the car died. Tried boosting again repeatedly but no luck.

I think I'm dealing with two seperate issues though. Rough idle due to ECU "relearning" and probably a cracked terminal on the battery. Apparently the mechanic had a tough time taking off the positive terminal due to the corrosion. He may have cracked it.
If the rough idle persists I'll check the intake gasket.

 

Turns out I wasn't getting a good connection on the positive terminal. Re-cleaned it and snugged it up and everything is working fine.

After an hour of driving the idle has smoothed out but isn't perfect. I'm guessing after a couple more hours of driving time it will be back to normal.

 

Second update - I replaced the PCV valve but the problem still persists. Noticed that prior to car getting up to operating temperature that idle is fine (as the car is idling higher), but once it reaches normal operating temperature the problem returns.

 

Took battery out to replace headlight bulb...

I took the battery out of my 2005 LE to replace a headlight bulb and when I put the battery back in, it was idling about 150 to 200 rpm lower than normal. The check engine light did not come on until about two weeks later. It has a rough idle, but otherwise it drives normally. It currently has 103,000 highway miles. I replaced the original battery about 5000 miles ago and that did not cause any problems. Why now?

I have a ScanGaugeII and used it to check for error codes. I only got one error: P00171. I'll be watching this thread for sure. I'm glad I found this forum.

One more question, does running too lean cause damage or "burn" the valves?

 

Bigfoot, I'd recommend going to your local autoparts store and picking up a can of Mass Airflow Cleaner, then pull the MAF sensor and give it a good spray down. Can't hurt anything if you're careful, don't touch or damage the sensor wires. If my suspicion is correct, it might fix your problem. Let us know if that helped.

 

Its not the MAF sensor or the intake manifold. Open your trottle body and spary some throotle body clearner on a rag and clean the trottle body passed the trootle plate problem fixed. The TSB for the intake manifold is for a P0171 (Syteem to Lean Bank 1).
Just clean the trottle body with a rag like a stated and your problem will be resolved. Hope that helps

 

This may seem a bit out there, but have you checked if the O2 Sensors are operating correctly?

 

Subscribing to this thread with a link to mine as well: http://www.toyotanation.com/forum/showthread.php?t=345585
I have a low/rough idle as well. There is some very good information in this thread with a common underlying problem occuring for several of us. Most will assume iacv or intake gasket. The problem with the iacv is that it's expensive, the screws strip easily upon removal, and it may not fix the problem. None of us are getting codes from the ecm which makes it even more difficult to track down. Anyone considered the effects on the mounts with the vibration occuring all the time. Someone stated that they received a quote to replace mounts in the range of $600 (ouch).

 

This is a long shot as it usually sets a code and aplogies if it's been suggested before and I missed it, but given the stubborn nature of this problem for some, figure it's worth a look. An air leak at the fuel filler neck where the gas cap screws on can cause low idling, either from a issue with the gasket on the cap or a break or crack in the top of the neck housing allowing a leak. Easy enough to take a quick check so I thought I'd put it out there...

As a check if you're suspicious, you can put a bit of Vaseline around the filler neck right where the cap gasket meets the neck, both to seal it well (start the engine and see if the idle is better) and as a check for contact - when you put the cap on and take it off again, the gasket on the cap (which was dry) should have the Vaseline all around it indicating a complete mating of the gasket to the filler neck.

 

Subscribed. Having the same idle issues with my 2003 LE. And if I remember, it started after the battery was replaced a couple of years ago. Was about to replace the intake mani gasket and clean the IACV. I will first try the gas cap test.

 

Lew, have you checked for intake leaks using propane or carb cleaner yet? No sense swapping out the gasket if there's no leak...

 

I have not yet. I was going to do the gas cap test along with cleaning the maf first. I'll do that as well. Thanks!