this never really been resolved?

[nutter_owner]

I have a 2007 xlt that was bought with original spark plugs at 84,000 miles a couple years ago.
I was misinformed when I bought it and it does not have the towing package. I pulled a loaded trailer weighing about 5,000 pounds for a while with no problems, as it was rated for 6,000 towing.
I was driving pulling a slightly heavier trailer at 6,000 pounds last fall and upon hitting throttle hard I got the misfire code P0305. It had pulled this trailer over the mountains with no problems on this trip. It had 108,000 miles, so I had the original plugs replaced. They installed Motorcraft PZK 14E, and reused the original COPs.
When the winter was over we were coming back to Minnesota with the trailer on. Unless I really did slow acceleration and babied it it would flash the misfire on the dash, and not rev past 3,500 rpm. Found if I only ran it to 3,400 rpm it wouldn't missfire. It was P0305 mostly, sometimes P0300, once a P0306. I replaced cylinders 5 & 6 with new COPs.
Now when I was driving without the trailer I got a P0305 code again and the blinking lite at 3,500 rpm. I was advised to replace all the coils, so I did.
When it did a P0305 again (no trailer) I took it into the shop. He told me it was beyond his ability to go further.
So I went to another shop and he told me the plugs were the wrong ones. He replaced them with Motorcraft SP546X. And he replaced a coil on 5. On the way home I floored it and it came up to 3,500 rpm, missfire flashing. Took it back, he replaced the spark plug in 5. I took it home, same thing. He drove it and replaced the #6 COP, checked compression in 5 (180 lbs) and a leakdown test on 5. He said it almost immediately blew smoke out the valve cover. Reports the timing chain has some play (original), engine is very clean, rocker arms on left bank, fuel injection pressure, catalytic converters all ok. He said either sell it or buy a new engine based on the blowby!
I am finding it hard to believe a clean internally engine with 180 pounds of compression is shot. It now has 115,00 miles.
I see all over the internet about similar complaints, but no one ever seems to go back online with a successful repair.
Should I take it to Ford??

 

[JasonH]

Valve seals? Get a second opinion. A new engine is expensive so it would be worth it.

 

[twodollars]

Excessive crankcase pressure I would check out pvc. It's in driver rocker cover I believe. I'd also want a compression test on all cyl as a indicator of overall engine health before considering a new motor. Also reminds me of my 6.2, would set misc misfire codes under load and high throttle. A crank position relearn solved that for me on that truck. Was a 2013 I think.

 

[nutter_owner]

I realize first post was long, but additional info on it.
Using premium grade fuel helps the problem. Will still do it but takes longer.
No ticking on startup or when running. Drives like a new car until you floor it to pass or pulling a load up a hill and open throttle up to keep going. Even 2nd mechanic couldn't believe how nice it ran until he floored it from a dead stop. When doing WOT from dead stop it takes off like a Raptor, then hits 3500 rpm and misfires and won't go past 3500 if throttle still held wide open with the flashing lite.
Idling with oil fill cap off no pressure to speak of, the cap and filler tube are almost dry. Would think if blowby it would be oily trying to get out.
The car does have the RSC option, but no codes or anything to say its activating.

 

[nutter_owner]

Idling with oil fill cap off no pressure to speak of, the cap and filler tube are almost dry. Would think if blow by it would be oily trying to get out.
The car does have the RSC option, but no codes or anything to say its activating. Just thinking as it seems to be a rev limiter kicking in. From a dead stop with WOT it takes off and accelerates like a Raptor! Then, 3,500 rpm it stops reving up and misfires.
Oil consumption for 3,000 miles is 1/2 of a quart, but am sure some of that is consumed during the miss fire testing of car.
Premium gas seems to help, but it still ends up misfiring at 3,500
So far in last 5 months it's had 18 spark plugs (2 full sets + "trouble makers) and 9 coils. Its got to be something else.

 

[twodollars]

Do you have any type of diagnostic tool that will let you re order see live data?

 

[nutter_owner]

No I don't. Thats why I took it in to an independent shop. They said they had the tools to find out. Has anybody used a Ford dealership? They probably haven't seen one this old since 2010! But I wonder if they can go deeper or actually see whats occuring when it happens??

 

[JExpedition07]

Sounds like maybe clogged up catalytic converters backing up exhaust fumes on WOT runs. Why have they not replaced the fuel injector on #5?

 

[Timo2824]

Unbolt the cats and run it with open headers, if it revs over 3500 rpm the cats are clogged.

 

[nutter_owner]

I talked to a Ford tech. He suspects rocker slipped out, so I am pulling valve cover to be sure the shop actually did. The bolts and hose look like never touched, so Im going to verify.
He also said to remove both upstream O2 sensors and see if huge pressure shoots out at idle. He said those sensors dont always trigger a code.
Oh, also noticed if using premium grade gas drives better (kind of a stumble, almost like it needs to downshift, at times with normal throttle).
Am running a bottle of Gumout thru it now, I was also thinking of a clogged injector.