2006 5.4 rough idle

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Feb 16, 2022 | 10:09 PM

Trailer101

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Joined: Dec 2020

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2006 5.4 rough idle

I’ve got a 2006 5.4 with a rough idle and can barely pull it self up the driveway. Misfires like crazy but no codes. All the data I’m reading from everything is within spec but when I unplug the fuel pressure/rail temp sensor it runs amazing with not a single issue. I’ve replaced the sensor just for the hell of it and still have the issue when plugged in but runs great unplugged. Any thoughts?

Feb 19, 2022 | 09:41 AM

Johnny Paycheck

Fleet Mechanic

Joined: Jul 2019

Posts: 1,315

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How does the FPDM look back by the spare tire? I think it sits above the rear axle.

That’s one thing I’d look at before springing for a whole set of coils and plugs.

Feb 19, 2022 | 06:19 PM

redfishtd

Fleet Mechanic

Joined: Apr 2016

Posts: 1,653

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My guess is to replace fpdm on rear axle . When you unplug it the pcm goes into default input to fpdm . They corrode out and get water in them so they get really erratic. It has an alum back mounted on steel axle so electrolysis eats into it , new ones are mounted on plastic standoffs. . you need practice on lowering your spare anyway .