Changed Battery, Now getting a drop in RPM's

[GlowstickNinja]

OK, so I finally changed out that stock battery from the dealership. You know the whit servicable one. Well after replacing the battery my car dips down in RPM's every time I push on the clutch. Almost to the point that it stalls. This is the only thing i have done to the car, worked just fine with previous battery installed. The reason i traded out the battery is because it wouldn't hold enough amps to crank over my motor when it got cold. The car has 82k on it and is completely stock. other than a stereo system that works just fine and did on the previoud battery. Furthemore i can turn off pretty much anything electrical and it still does it......Any ideas would be much appreciated.

PS I used to drive a volkwagen jetta, and when you disconnect the battery you would actually have to touch the negative and positive battey cables to completely discharge the system. If you didnt the call would stall above 1100rpms. Anyone know if this is the same case with the mazda?

 

[pro5utah]

you probably just cleared your ECU when the battery was out....drive it a while and the problems will most likely go away as the ECU relearns....

 

[adc0642]

I have the exact same issue. Changed the battery because it was going weak. Then erratic idle.
I came to the same conclusion: it reset the ecu and it's remapping.
BUT!! I've had the battery disconnected for extended periods in the past (ie installing radio, etc) and never had this problem.
So we'll see in time if it goes away. Otherwise, according to a quick forum search, it could be dirty egr.

By the way, did you move intake plumbing around to change the battery?
I just popped off the strut tower bar instead. took 10 min total.

 

[kapps28]

i just got my battery changed a couple days ago. haven't had any problems with my car at all, including a dip in the rpms or anything like that. i was kinda of expecting something like that to happen since i assumed my ecu would be reset, but i guess not. everything is working top notch for me right now...

 

[adc0642]

congrats on no issue. i have never had this happen on any other car, and i've changed a lot of batteries. often the car will drive a bit different for the first few miles as the ecu re-learns; but this is weird.
What's doubly weird is it's hitting random cars, and only after changing the battery...
I'm starting to wonder if maybe it's a combination of a semi-fouled egr and the reset ecu. If the egr fouled over time the ecu would be able to compensate to a piont, and maybe show no symptoms. Then with the re-set, it's trying to learn all over, but it's so far off the base map it's taking some time.
I'll give it a couple weeks, then whether or not the problem goes away, i'll check the egr.

 

[kapps28]

i also went to the dealership to get my battery changed...

don't know if they did anything special to it during the change to make it so the ecu didn't reset or anything...just thought i would let you know that bit info...

 

[GlowstickNinja]

Everything runs great now, ECU relearned and now all is good thanks yall!

 

[adc0642]

Everything runs great now, ECU relearned and now all is good thanks yall!

oddly enough, same here. All is now smooth. I suspect egr is partially plugged - will clean in a week or so.

 

[P-Funk!]

I would have said (if it had not cleared up) that you had a bad battery (bad cell). If the alternator was full-charging all the time - it might drop the idle...