2003 Ford Focus

  • 2003 FORD FOCUS
  • 4 CYL
  • 2WD
  • 78,000 MILES
My car jerks and hesitates when I hit the gas. Alot of people are telling me that it could be my fuel filter or my fuel pump any ideas
Do you
have the same problem?
Thursday, August 28th, 2008 AT 10:41 AM

1 Reply

Could be all these things, but it could be many other things as well.
Is your 'check engine' light on?
I would start by checking for DTCs.
You could have a misfire going on (in which case further diagnostic will be necessary).

Possible causes include:

- Dirty or leaky fuel injectors
- Bad MAP (manifold absolute pressure) sensor (I'm not sure if Focus have this sensor though)
- Bad TPS (throttle position) sensor
- Bad or dirty MAF (mass airflow) sensor
- Low fuel pressure
- Vacuum leaks (intake manifold, vacuum hoses, throttle body, EGR valve)

and in some instances. Bad fuel!

There is a few easy things that you can do to help diagnose and maybe fix your problem:

- Do a fuel pressure test. This will tell you if your problem comes from a lack of pressure (due to a bad pump, filter, damage fuel line, regulator etc).

If pressure is too low:
- your pump output could be too low (weak pump, low voltage to the pump)
- or your filter is clogged (when was the last time you replaced it? I think Ford recommends replacing the fuel filter on focus every 30,000- 35,000 miles). Although it's not a very accurate test, you can try to remove it and blow thru it to check.
- or your fuel pressure regulator is messed up (disconnect the vacuum line from the regulator and check for gas in it; if there's gas in it, the diaphragm in the regulator is messed up and you need to replace the regulator).
- you could also have a leak somewhere including leaky injectors.
- it could be your inlet filter sock that's clogged. (If you replace your fuel pump, make sure you replace the sock as well)

Other things you can do:

-Buy some electronic cleaner, remove the air duct from the throttle body and clean your MAF.
- Put some fuel system cleaner in your tank to clean fuel injector and fuel system (put it in a full tank).

- check for a vacuum leak (intake manifold, and vacuum hoses, throttle body, EGR valve etc)

Good luck!
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Thursday, August 28th, 2008 AT 5:01 PM

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