This is on a 2006 Mazda 5. The car starts just fine idles great, you can accelerate just fine but when you take your foot off the accelerator the idle drops to 250 and bounces from 250 to 750 and occasionally dies. The only thing that has been done to the vehicle is the battery got changed the day before this started happening but I can't see it being an issue unless the is some sort of computer reset that you have to do after installing g a new battery. Also it has been pretty cold since the battery change (between 0F and 15F) so temp could have something to do with it. Would appriciate any ideas that anyone might have at this point I am thinking maf sensor.

 

I have an 06 M5 and am having the exact same problem. I replaced my battery on Tuesday and the problem was immediate, our weather has been between 15 and up but I have had the car in that weather before without a problem.

 

If you figure out the problem please post the solution I don't know when I'm going to get a chance to troubleshoot it

 

I believe I got the problem fixed and if your a person that works on Mazda a lot then you'll probably at the fix. So what I did was let the car run in idle til it was nice and warm then I put the car in drive and let it idle there for another 5 minutes or so. I then took it for a drive and found none of the symptoms that I had before. After all that I checked another Mazda forum only to find out that running your car in idle for 5 minutes is standard operating procedure after you disconnect the battery. Hope this might help someone else.

 

Thank you very much for your post. You saved me a lot of time and money, since our 2007 Mazda 5 (64,000 mls) had the same symptoms after I disconnected the battery. I was already close to buy and change the purge valve and even other parts too. Luckily I found this forum and tried the above described procedure of "idle learning". Car works perfect again.

Note: I tried the procedure without having warmed up the engine, it didn't work. So i tried again after the engine was warm ..... and IT WORKED !!

 

EXACTLY! After a battery change the computer needs to re-learn. As soon as you pick up your vehicle you should do the above! Drive it around for 50-100 miles (not necessary all at once) before you report any problems.
If you are having problems, check your air intake hose for leaks (cracks) from filter box to throttle body as this may have been removed. Any leaks in this area can be temporarily fixed with Duct Tape!

 

Idling is controlled by an IAC valve. Idle Air Control . If this valve is dysfunctional the air will not make it's way through this valve to bypass the throttle plate into the engine to keep running. In the 2.3L engine this valve is underneath the throttle spring held to the throttle body by two bolts. It may need cleaning with a solvent but in most cases need to change as very unlikely carbon wouldn't settle there. In other instances you may need to change the. MAF sensor and purge valves