Stumble Under Load

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Jun 7, 2011 | 12:54 AM

jd1083

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Stumble Under Load

I have been noticing that my '01 5.4L has been stumbling slightly when accelerating lately. It doesn't do it all the time but occastionally when under moderate acceleration it would stumble around 2200-2800 RPMs. Today while pulling a trailer (probably a 2000-2500 lb load) it began to stumble quite noticeably, especially when climbing hills. Cruising down the road it ran fine but when put under a moderate load it stumbled quite a bit. What could be causing this? Plugs? COPs? Bad fuel filter?

Jun 7, 2011 | 02:02 PM

jd1083

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Bump. Any ideas? I have to tow a trailer 300 miles tomorrow and would like to fix the problem before I depart. Thanks.

Jun 7, 2011 | 02:04 PM

senix

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From: Frederick, MD

I'd take a look at the COPS myself.

Jun 7, 2011 | 02:05 PM

A/Ox4

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From: Missouri

In my 5.4 I had bad spark plugs. I changed the COPs too. I took it to the dealership and they told me there was a fuel injector recall on the engine. They looked at it and found a bad injector, then they found out that the catalytic converters were bad, because of the fuel injector. Mine was a 3V and yours is a 2V. Call your dealership and ask if the fuel injector recall applies to you. If not change your plugs and COPs.

Do you have any codes?

Jun 7, 2011 | 03:42 PM

jim0517

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I would check your vacuum lines first. Especially near the fuel rail on the drivers' side. Vacuum line goes to the fuel pressure regulator there. I had a stumble under load at times. Turned out that the vacuum line broke off from the regulator.

Jun 8, 2011 | 07:01 PM

jd1083

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Thanks for the suggestions. I ended up pulling the trailer with my other truck in fear of the F250 messing up, but I'll check the plugs, COPs, and the vacuum lines once I get back home.

Jun 10, 2011 | 07:25 PM

jd1083

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I didn't have time to change the plugs or COPs yet but I plan on doing it tomorrow or Sunday. I drove it today and it drove fine without and stumble or hesitation at first, but after driving it for a while it began to stumble again under load. Could bad plugs or COPs cause a hesitation once the motor warms up?

And BTW every time it has acted up it has been hot outside (90+ degrees) and it was 100 degrees today.