2003 Ford Focus Misfireing or missing

2003 FORD FOCUS
73,563 MILES • 4 CYL • FWD • AUTOMATIC
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MARTY MARTINEZ
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  • 2 POSTS
This started this past Friday. I took the car to Autozone and asked them to scan the codes.They said that it was a misfire and a misfire on #4 bank.
I changed the spark plugs and there was a slight improvement. But a little later, hour, it started again.
The motor light took a little while to turn off but, when i pushed the accelerator a little hard the light came back on. Also the misfiring started again.
I put my hand all over the spark plug wires and did not receive any spark at all.
What else can I do?
Jun 28, 2010 at 8:01 PM
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JACOBANDNICKOLAS
  • CAR REPAIR CONTRIBUTOR
  • 110,190 POSTS
I need you to remove the new spark plug from #4 cylender and tell me what it looks like. Also, if the vehicle still has the OEM plug wires, I would replace them. Let me know what you find.
Jul 3, 2010 at 1:45 PM
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MARTY MARTINEZ
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I have changed the spark plug wires.I do not know which one is #4bank or cylinder.Looking at the motor,it would be the last plug on the very right,going from left to right. I took out this plug and it was a little black at the base of the electrode.
I also, took out all the plugs and made sure that all were still gaped correctly. That is when I saw the fourth plug a little black. The rest were clean.
Jul 4, 2010 at 11:45 AM
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JACOBANDNICKOLAS
  • CAR REPAIR CONTRIBUTOR
  • 110,190 POSTS
The black usually indicates that it is running rich. We may have a fuel injector problem or a fuel pressure regulator problem.

I need you to watch the following video and the review the directions on how to check fuel pressure and the regulator. You will need a fuel pressure gauge. Most parts stores will lend or rent one to you.

Check the fuel pressure and regulator and let me know what you find.

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm

Joe
Jul 4, 2010 at 10:22 PM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.