My battery recently died and I replaced it with the same Bosch 35 since it was under warranty. Ever since replacing it, my idle is extremely rough, slipping down to around 500rpm every single time the engine is revved, in which the car vibrates fairly rough. I took it around for a few blocks and stalled probably about 6-7 times when coming to a stop, then decided to just take it home for now.

Don't think its normal for it to stall like that after changing a battery...Any input?

 

I had this same issue not too long ago and it was a combination of my coils and plugs. After I replace them my problem was solved. Did you get any CEL light?

 

Its the ECU re-learning the fuel trims. After you run the car few a drive cycles idle will be back to normal

 

yeah, dont let the car die on you, just keep the revs up at about 3k for about a minute and you should be fine

 

hey guys im having some prob with my battery or spark plugs. every time i start the car, it takes about 4 sec or so to actually start. also, every time i go up a hill or mountain, the car really loses power. i bought the car used from a mazda dealer ship in july of last year. any one know the prob?

 

get your compression tested.

 

any idea how much thats gonna set me back?

 

I had this problem last week when i replaced my battery along with coils, wires, and plugs. I was afraid that I'd screwed up the installation. Like another poster said, it was relearning the fuel trims and after driving it for a few days, it got progressively better until it's back to normal now. good luck.

 

first start by replacing the coils, plugs, and wires. you're going to have to do that first anyway. if that doesn't work, then try the compression test.

 

Thanks for all the responses.

Yes, it was indeed simply just the ECU adjusting the fuel trims. I expected unstable idles, but didn't think it should have stalled. Which leads me to believe I may have some other issues as well. Probably time to get new coil/plug/wires as suggested as well. I'll try that first.

 

if i get a tune up will that cover the coils, plugs and wires? or would i need to ask them just to replace to 3 things?

 

The car is learning its air fuel ratio again. Every time you unplug the battery cables the ECU is reset. All you have to do is to drive the car 3-4 driving cycles (start the car, drive for a bit, turn off the car= 1 drive cycle). Do this for 3-4 times and the car will get back to normal. Plugs and coils should not give you trouble with idle but with performance (e.g. misfire, hard to start the car, power loss, etc).