My Ford Focus runs roughly for the first few minutes as the ECU is probably figuring itself out.

Hello OP

The reason your Camry behaves that way after your battery is disconnected is because your cars computer has to re-learn it's idle speed. This is common in some older models of cars. I have a 2006 Camry that behaves same way but I know 2008 camrys don't have the same problem.

The process of re-learning it's idle speed is what causes low RPMs after starting or causes your car to stall completely.

As you've rightly observed after the engine has run for a while everything goes back to normal.

One quick way I've found to force the car to re-learn it's idle position quickly is to start/stop the car several times ( not up to 10 times but I didnt really count).

On each start if you observe the rpms dropping and it feels like the car is about to go off just turn off the engine and repeat the process again. After a while you will notice a clean start and normal rpm operation which means the computer has stored the new idle setting in its memory.

Iarocha:
Hello OP

The reason your Camry behaves that way after your battery is disconnected is because your cars computer has to re-learn it's idle speed. This is common in some older models of cars. I have a 2006 Camry that behaves same way but I know 2008 camrys don't have the same problem.

The process of re-learning it's idle speed is what causes low RPMs after starting or causes your car to stall completely.

As you've rightly observed after the engine has run for a while everything goes back to normal.

One quick way I've found to force the car to re-learn it's idle position quickly is to start/stop the car several times ( not up to 10 times but I didnt really count).

On each start if you observe the rpms dropping and it feels like the car is about to go off just turn off the engine and repeat the process again. After a while you will notice a clean start and normal rpm operation which means the computer has stored the new idle setting in its memory.

I think another way to resolve the issue of low/unusual RPM when in idle is to clean the throttle body as dirt must have clogged the normal air passage when car is in idle position and the car's ECU will have to relearn to compensate, hence the unusual RPM. I experienced same too when ever I disconnect the battery of my Corolla 2006 till I read about it and cleaned the throttle body. Now its fix battery, start and go.

The only thing I have to reset myself is the radio stations and the automatic door lock.

Never experienced such on Honda. My 05 accord works like nothing happened when u remove and reconnect battery. 05 pilot same thing except for asking for radio code and the driver side auto windows would not work. The power windows will work but the automatic will seaze to work, it is reprogrammed by whinning the driver's power window all the way down, then whine it all the away up and bam, auto windows is back.

In Peugeot 306 and possibly all Peugeots, what you get when you replug is that your cooling fan no longer has control, it'll just be working on till his kingdom comes, unless you have an auto rewire bridge it for you.

Benjom:
Noted... It's good to be enlightened... Thanks for the observation OP.

Autojosh some cars come up with "syndromes" if you remove battery while the key is in the ignition


Rover 75 for example does that

greenhulk:
Never experienced such on Honda. My 05 accord works like nothing happened when u remove and reconnect battery. 05 pilot same thing except for asking for radio code and the driver side auto windows would not work. The power windows will work but the automatic will seaze to work, it is reprogrammed by whinning the driver's power window all the way down, then whine it all the away up and bam, auto windows is back.

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Day11:


Contact Day11 Service

We retrieve back Radio Code within a min

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Thanks. Actually I don't have radio code problems, I do have my radio code. Moreover I changed the OEM radio to an aftermarket DVD with Nav. I'll refer u if I have anyone with radio code problems.

uboma:
my car do not have any issue like the ones listed by the op whenever the battery is reconnected.

the only thing I have noticed though is that the MPG reading no longer shows.

I am still looking for the trick to bring it back on.

my car is a BMW 323i Touring 2000 model.

Meet a rewire the device is inside your fuel tank attached to your fuel pump.