JSR_AP2

This has happened about 2-3 times since I've owned the car (for about 3k miles now). After driving for a bit and I come to a stop light, the engine will idle at a higher rpm, about 1.5k-1.7k. It will stay there if I don't do anything, but if I blip the throttle a bit, it will drop back to the normal 1k. Is the butterfly getting stuck?...is anyone else experiencing this?...should I be concerned? This is virtually impossible to replicate purposely, so going to a dealer may not help (they always want to see it happen). It just happens when it wants to. Thanks for you help.

pepelepew916

mine did not go up.. but it went down to almost stalling. This happen especially right after fueling or when I'm reversing and then stop. Any input?

revhi

AP2, never heard of that happening, Pepe, thats normal.

Both of you should try whacking your map. No, but seriously.

xviper

It could as simple as your cars having a momentary "brain fart", in which case, don't do anything like blipping the throttle or trying to save it. Let it do what it does and it should learn to compensate after a few episodes. The ECU is trying to adjust for varying atmospheric and climatic changes going on in your area.
However, it may also be possible that the Idle Air Control mechanism is sticking or having some problems. This too, could only be temporary and correct itself. Of course, there's the old MAP sensor situation. Do the MAP whack (including the harness disconnect/reconnect) and ECU reset if the problem persists. You might also look into the new MAP sensor TSB, which is basically securing the MAP harness solidly.

pepelepew916

does your ECU learn your driving habbit? Like for example, somtimes I drive my car hard... VTec as much as possible, and the next day I feel the car more responsive. Other days I take it easy, 3rd gear on 30mhp, 4th gear in 40 and the day after I feel the car is less responsive when I hit the gas or maybe it's the music that I listen to?

xviper

I don't think the ECU is "that" smart. It may be "adaptive" to some extent. It runs the engine based on what the sensors tell it. It can "learn" certain conditions as being odd or the "norm" and use those as long term parameters. Things like coolant temp, intake air temp can change rapidly. Humidity, air pressure, condition of air filter and numerous other things can add to the "confusion" at any given moment. Of course, the way you drive the car can also contribute to how the car will drive in the next hour or the next day.
If you feel the car being stronger because you drove it hard, it could be in your head or it could be that you blew out the crud from your exhaust system.
For example, I've also noted that in the summer, after the engine and underhood temps get really hot and I've run it hard, then come to a red light, the engine will have a near death experience. This is even worse when the A/C is on. After a few of these episodes, it figures out that the idle goes too low and it compensates on it's own. The more I try to "save" it, the longer it takes to learn and the more episodes it takes. Then there's the change from fall to winter "near death cold start blues". For the first 3 winters, for about 4 to 5 mornings, the engine would start, rev up and immediately die, requiring a second start. I can prevent it from dying by feathering the throttle at the moment of ignition but it will continue to need the feathering for a very long time. If I let it die a few times, it eventually learns on it's own. For some strange reason, the 4th winter and this one (5th) it did not repeat this phenomenon. Go figure. It's almost like the ECU can't seem to learn fast enough when sensor readings are suddenly and vastly different from what it's been accustomed to.

JSR_AP2

I've never had the problem with too low an idle. I'll give the MAP a whack once it happens again and do the reconnect/disconnect. My car is a MY04, so does the MAP sensor TSB even apply?...I thought that was for MY03 and older cars? I'll let it idle high the next time it happens and just start driving once the light turns green...hopefully the ECU will fix it. Thanks xviper and everyone else!

pepelepew916

yep! thank XViper for the detailed explaination .. wish you're in CA

xviper

This TSB applies to any car that exhibits the conditions stated in the description of the symptoms regardless of year. It's to do with the securing method used to hold the harness on. I'm not sure if Honda will begin to release cars from the factory with this "holder" but any car that doesn't have it and shows the symptoms should qualify for this TSB. However, Honda has only designated one particular set of symptoms that will grant the TSB to be done. This involves hard acceleration resulting in a non-smooth rise through the rpm band (a "hiccup" or miss).
But we, as owners, have discovered that a bad MAP connection can lead to many other odd conditions which a MAP whack and ECU reset have cured on more occasions than can be attributed to fluke.