2007 Cyl 3 misfire

[JustWarminup]

Hey all!
Have a 2007 Expedition with a misfire on cyl #3 under heavy acceleration above 3500RPM. At all other times it runs great. Also sounds like I get some ticking and lash on the valve train during 4500rpm and up.

Changed plugs, coils, injectors, VVC, phaser, Rollers, lash Adjusters. everything short or tearing the head off.

Cats both run exact same temps and no signs of clogging.

did the HV360 oil pump (believe that was the # [the high volume version of oil pumps]) Mechanical Lash Adjusters, Chains, Guides.

Trying to save myself the effort of a tear down again, anyone have any other suggestions?

Compression test is next move and will see if how a leak down performs. Over an hour or two.

 

[Hamfisted]

What weight oil are you using ? You can do yourself a favor and use at least a 5w-30 oil. But sounds like you did everything else you can do.







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[nutter_owner]

exact same symptoms my 07 has, except mine in usually cylinder 5!
I have 115,000 miles with original chain, phasers, etc.
Mine wont rev past 3500. Just going out to pull valve cover to double check a shops inspection for springs and rollers.
I talked to a Ford tech, he said to recheck the rollers in mine, and also suggested pulling out the O2 sensors ahead of the converters to see if a large pressure at idle. He said the sensors sometimes wont trigger on them. Thats next on my list today

 

[JustWarminup]

Running 5w-30 already, thought there might be issues so i changed the filter out.

o2 sensors have good response times but that might be a good option to check and see if they are shot.

Sometime this week is the compression test.

 

[Adieu]

#3? Check for a small coolant leak from around the T.

It gets into the coil and injector wells that are perfectly positioned for that to happen.

And coolant *never* evaporates so it just sits there until it seeps in and screws up the coil and/or injector.