Is there a Schrader valve on the fuel rail to pressure test the fuel?

[docraymund]

Yes you need to buy an adapter and connect it to the fuel line. That's the only way. And if you can, get an exhaust backpressure gauge. That will surely verify your cat problem.

 

[1955moose]

I think Doc is right, some of these Expeditions don't have the test port. But look on both sides of the fuel rail. If you have one, it probably still has a cap, like one on a tire has. If you don't have it, you or your tech, will have to T into the injector line to test pressure.


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[The Swagonmaster]

On my 07 the Schrader valve is on the drivers side fuel rail.
As a recommendation, pull all of your spark plugs and check or replace them. I had a heck of a time finding the bad one in mine because it was bad enough to miss fire sometimes but not bad enough to set a code.

 

[1955moose]

In the past we would hook up vehicles to a huge Sun diagnostic machine. It would show the firing of each cylinder, you could cancel each cylinder, and see the kilovolt readings of all 8 cylinders of the engine. You could see a spike in the cylinder that was acting up. These days Snap on or one of the better equipment manufacturers have it built into a much smaller unit. Still the tech working on it needs to figure out the origin of the miss.


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[Trucker14]

In the past we would hook up vehicles to a huge Sun diagnostic machine. It would show the firing of each cylinder, you could cancel each cylinder, and see the kilovolt readings of all 8 cylinders of the engine. You could see a spike in the cylinder that was acting up. These days Snap on or one of the better equipment manufacturers have it built into a much smaller unit. Still the tech working on it needs to figure out the origin of the miss.


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I'm actually taking it to a mechanic my friend recommended who has one of these big fancy machines lol. I'm only trusting my friends recommendation bc he usually does his own work as in depth as tranny builds, but if he hasn't got the time, this is the only guy he trusts to turn a wrench on his trucks.

This guy only charges 20 bucks to use his machine too. He said he's found fords tend to display the wrong cylinder on the cheaper diagnostic tools that's creating the misfire. At least some times. But I've got the lisle spark plug tool on order, that way I can replace them all if that's the case.

 

[1955moose]

When your working on a non computer car or truck, those old Sun diagnostic machines are great. Years back I was a service writer for the old Montgomery Ward auto. We had a young tech that just did a full tune up on a Dodge b200 van. He had a miss fire after plugs/ wires install. He fired up the big beast tester, found out those crappy champion spark plugs that Mopar recommends, one was bad straight out of the box. The cheaper code readers for obd2 systems will do the same thing as the more expensive ones, but they won't do the delicate stuff that's needed. Also they don't tell you which wires/ systems to check to get rid of code. Does cost a lot more for the bells and whistles though. Usually $500.00 and up, way up!


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[Trucker14]

Yea the one this guy has was in the thousands lol. If he thinks it's just spark plugs after he looks at it, I'll do those myself and save a couple to a few hundred lol. But if he finds it's a timing issue like a cam phaser, I'll just give it to him lol

He told me one time he did plugs on one of these and all but one broke lol. Took him 8 hrs to do that plug change. Said normally he doesn't break more than 2.

 

[1955moose]

Yeah, these oem spark plugs must have been designed by Satan himself. It would've been bad enough if they broke, and you still could get the socket on the nub part that broke, but no to have to use an extractor in a nightmare location, I'm sorry that's just ludicrous. I've had my share of tough cars/ motorcycles over the years, I've worked on but to have this design after the first generation thread issue is insane. I guess Ford is making too much money and doesn't worry about customer loyalty. Can you imagine what customers wrote about how they liked their purchase back in 2005-2008. That must have been great reading, and oh the language!


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[Ranger Jim]

If your Oil level is very low, you can loose pressure to the Cam Phasers and the engine will misfire with a distinct clicking sound, and the transmission my appear to slip/pause as it tries to determine what gear to be in with a slight load and less than normal power.

The very low oil misfire symptom is made worse during a long turn, like a curved highway on/off ramp.

I filled with 0-20 synthetic and the start up clicking goes away in less than one second, power is better than ever.
(new plugs and Coil boots and springs, sanded spring contacts to remove corrosion on Coil packs)