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Well, when your engine is warmed up, the car is in open loop mode while driving, meaning it uses the MAF for calculating A/F mixture. If idling when the car is warmed up, the car will start out in closed-loop mode, meaning it uses the 1st O2 sensor to calulate the A/F mixture then switch to open-loop mode after the TPS/RPM's hit a particular threshold and the O2 sensor senses there is sufficient airflow detected.(This is theorized but you get the idea between open and closed loop mode.)

Also, when your car is cold, the engine stays in closed-loop mode until the ECU believes that the car is warmed up enough to go into open-loop mode.

Enough theory....


So, does the car die at idle or while your driving ?

When was the air filter last changed ?


98 Contour GL/03 ZX3 Focus/05 ZX3 SES Focus
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Originally posted by microtonal:
So, does the car die at idle or while your driving ?
When was the air filter last changed ?




The car will die when accelerating away from being stopped at a light and several times in a parking lot after starting and slowly driving away. No rocket starts, just normal driving.

We just bought this car(no warrantee) and at that time was fine. I will check the air filter as I have not done that.
_Fred

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Um, seems like there might be an issue from handoff from closed-loop to open-loop mode.

I would remove the MAF and take a look at the wires and see if they are dirty in anyway. You'll need a T-20 torx security bit to remove it.

It does sound like a MAF problem though.

You might also want to make sure the MAF harnest connection is secured.




98 Contour GL/03 ZX3 Focus/05 ZX3 SES Focus
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Don't remove the MAF. Just open the locking tabs from the MAF to the Filter box and pull the hose out. From here you can look right at the MAF sensor wires.

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Well since my last append the car has not stalled according to my son. He's still nervous though as he should be. I did take a look at the air filter and it was new. For now I will continue to ask my son daily if any stalling problems and if so, then concentrate on the MAF sensor with all your suggestions everyone as being a most likely candidate. Thankyou so much.
_Fred

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