Car stalling randomly… anyone know what’s wrong?

Automotive Forums
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My dad’s car has been acting up lately, and we’re trying to figure out what’s wrong. The car will stall randomly at lights and won’t start again unless the battery is disconnected for 10 minutes. Then it runs fine for a few hours before the issue returns. Sometimes it runs perfectly all day.

Today, the car revved up to 1100 RPM by itself, stalled when trying to shift into gear, then eventually went back to 750 RPM for about 30 minutes before starting to stall again.

The car is a 2010 Ford Falcon BF Mark 3 station wagon with 300,000 km, a 6-cylinder engine, runs on gas, and is automatic.

What’s been replaced so far:

  • Mass airflow sensor
  • Throttle control sensor
  • Alternator and battery
  • Ignition coils
  • Converter

The throttle body has been cleaned, air lines have been checked for leaks (no changes in RPM), and there are no fault codes. My neighbor, who used to be a mechanic, has tried helping, but he’s not sure what the issue is either.

We’ve spent a lot on parts and are running out of ideas. If anyone has suggestions, we’d really appreciate it!

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Thanks for sharing your question on this forum! Please include as much info as possible like the car’s make, model, year, mileage, and any work you’ve done. This helps everyone offer better advice.

Let’s keep discussions friendly and on-topic. Serious answers only so we can all help each other out!

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Just to add, the car has 300,000 km and a 6-cylinder engine. Thanks in advance!

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Are you sure it’s the MAF sensor that was replaced? Did anyone run an OBD scanner to check for error codes?

5

Finch said:
Are you sure it’s the MAF sensor that was replaced? Did anyone run an OBD scanner to check for error codes?

Yes, the mass airflow sensor was replaced, and no error codes came up on the scanner.

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@Jade
If there are no codes, it’s usually either a fuel or spark issue. I’d start by checking the fuel pump and filters.

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Finch said:
@Jade
If there are no codes, it’s usually either a fuel or spark issue. I’d start by checking the fuel pump and filters.

Thanks! He’s been thinking about replacing the ECU. Do you think it’s worth a shot? He’s also replaced the ignition coils and converter recently.

8

@Jade
The ECU would be my last resort. You might also try bumping up the idle speed and seeing if it runs smoother. Does it run rough before stalling?

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Finch said:
@Jade
The ECU would be my last resort. You might also try bumping up the idle speed and seeing if it runs smoother. Does it run rough before stalling?

He said he can increase the idle speed, and it runs fine until it randomly drops to 600 RPM and then wants to stall.

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@Jade
600 is pretty low. Try setting it closer to 800.

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Finch said:
@Jade
600 is pretty low. Try setting it closer to 800.

The problem is it drops on its own. Today it shot up to 1100 RPM, stalled when trying to shift, then settled at 750 for a bit before starting to stall again. He checked for air leaks but didn’t find any.

12

@Jade
This sounds like the ECU isn’t getting good readings. It could be the MAF, crank, or cam sensors—but the lack of error codes makes it tricky. I’m stumped, sorry.

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Finch said:
@Jade
This sounds like the ECU isn’t getting good readings. It could be the MAF, crank, or cam sensors—but the lack of error codes makes it tricky. I’m stumped, sorry.

No worries, I really appreciate your help. He’s going to try replacing the ECU tomorrow. Fingers crossed it works!