# PLEASE help Mazda 626 stalling



## PJofSMK (May 22, 2005)

My 2000 Mazda 626 stalls while idling. The check engine light is on, so I took it to my local autozone to have the code read. The guy told me the fuel was running rich/lean and it is most likely the O2 Sensor. I wanted more help so I got motortrends PC auto diagnostic program. The info I got from the program is that it could be the "idle air bypass vavle".The car will stay running if I slightly press the gas pedal and drives fine while accelerating. 

Also, the O/D light just started flashing yesterday.It shifts fine, but I am concerned about the O/D light flashing.

The car a 4 CYL Automatic. Any info would be appreciated, thank you.


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## StaticInMyHead (Sep 27, 2004)

Is the idle just too low? Dirty spark plugs? Maybe the fuel injectors are clogged? Weak fuel pump? Another possibility is the little 'computer' that controls your oxygen sensor; it's very likely that it has a problem. That's just the thing about those...they run great when they are running. If not, they are always difficult to maintain. 
I'd suggest adding some fuel treatment to see if that frees up any junk in the fuel lines. You could also check the pressure in the fuel injectors. I'm not too familiar with Mazda, but when you turn the key to the 'On' position it should pressurize the lines. On the fuel injection unit there should be 5 lines running from it. One large line and 4 smaller ones. Loosen the nut holding one of the smaller lines in place, I'd say about halfway. Don't touch any of the other lines; make sure they are all tight. Have someone turn the key over and check to see that fuel sprays out of the injector. The higher the pressure, the better. Be careful to protect your eyes. Do that to all four of the injector lines, and if they all spray with decent pressure, then your fuel pump is okay and your fuel lines are clear-it is probably the oxygen sensor failing. If the line pressure is low, then check out your fuel pump to see if it might need to be replaced. Hopefully not, as they can be extremely expensive...
Good luck.


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## jimd2p (May 22, 2005)

Any chance you can give me the exact code? From that I could actually provide you with a diagnostic flow chart. There is a big difference between an IAC motor and a failing O2 sensor. The IAC motor will cause your symptoms more. 

Also, on the 626, as well as most modern EFI cars, the injectors are electronicly controled. There is no nut to break loose and it is extremely dangerous to try to check for a spray pattern without the proper equipment. There is usually 2 10mm bolts holding the fuel rail on that hooks to the injectors, and then a 2 wire plug to each injector that is controlled by the PCM to tell the injector when to open and close. 

Again, a specific code would help since there is a big difference in the two items you are referring to. Since that is an OBD-II system, the code should start with a P and have four numbers. 

With the OD light flashing, you should be able to pull a transmission code too.


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