5.4 Miss

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Dec 8, 2006 | 08:54 PM

hush210

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5.4 Miss

My work truck(a 2000 E-250 with a 5.4 and an auto) started missing the other day. Im planning on new plugs and wires bu is there anything else that could cause it to missfire?

Dec 8, 2006 | 10:57 PM

LxMan1

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From: Louisville,Ky.

Yes, the common problem is a COP (Coil On Plug)
Is you check engine light on? If so, have it scanned and it will tell you which cylinder is missing. That coil is probably bad.

Dec 9, 2006 | 07:37 PM

hush210

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The check engin light came on after it started missing. Is that what they do?

Dec 9, 2006 | 08:11 PM

Wilber15

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From: Duluth, MN

If you know the cylinder missing, swap the COP from the bad cylinder with a cylinder next to it and see if the misfire moves to that other cylinder. If so, you know it's a Coil On Plug. If it stays, it's either a injector problem or mechanical problem(valve/piston/ring)....

Dec 10, 2006 | 04:06 AM

LxMan1

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From: Louisville,Ky.

Yes, the check engine light will light. Run it by AutoZone for a free scan and post the code here. We can decifer it for you.

Dec 24, 2006 | 02:37 PM

Galveston Yankee

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From: Galveston, TX

Also check your air filter. A disruption in air flow will cause it to miss.

Dec 24, 2006 | 07:33 PM

projectSHO89

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From: St Louis

Quote:

Originally Posted by Galveston Yankee

Also check your air filter. A disruption in air flow will cause it to miss.

Very unlikely on a computer controlled engine.

Get the codes read. They are your next clue in the diagnostic process.

Steve

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Dec 31, 2006 | 11:39 AM

redford

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From: Stephensville WI

Quote:

Originally Posted by projectSHO89

Very unlikely on a computer controlled engine.

I disagree. I have seen it happen on poorly maintained vehicles. The engine tries to compensate for the lack of air by restricting fuel, keeping the F/A ratio good. Eventually your weakest cylinder will start misfiring . Soon the computer cannot adjust the F/A ratio to keep it in tolerance, you get a rich mixture at that point.

It's one of my pet peaves with modern engines, they mask bad maintenance pratices. The engines run good until the computers can no longer compensate, then the people think they have a sudden breakdown and blame the engine.

In any case, pulling the air filter will tell you right away if this is the problem, but with these engines a COP is the likely cause.

Last edited by redford; Dec 31, 2006 at 11:54 AM.