2005 Lincoln Aviator Misfire Cylinder 5, 6 (P0316, P0306, P0305) Help?

[dmcage1]

OK, so I have a 2005 Lincoln Aviator, comes standard with a 4.6 (just like the Marauder). I have replaced the crankshaft position sensor, camshaft position sensor, spark plug, fuel filter, ran Lucas fuel injector cleaner, and replaced OEM coil packs with Accel coil packs and I still get a misfire. I cleaned the throttle body, Mass air flow sensor, and the Idle Air Control valve. Also checked the coil pack fuse.

I have rotated the coil packs and the problem does not seem to follow so this leads me to believe there's something wrong with the cylinder. I pulled the plug and noticed a viscous material at the bottom of the spark plug in cylinder 5. I think it might be oil? If so, that explains the misfire. It tends to misfire when I'm at a complete stand still, above 7500 RPM's and you can't tell. I currently idle around 6000 RPM. Is that low?

Is this caused by a valve seal being broken or an intake gasket leak? If it is the valve, do I need to take the head off? Am I missing something that I should have checked? I will run a compression test later this evening and will report the results back. Last thing, I pulled my new Accel coil pack off and it's rattling while none of the others are, I'm assuming it's now toast?

Also, would anyone know where the fuel pressure check valve is? It's not on the fuel rail that I can see. Most say it's on the end towards the front of the vehicle on the driver's side, but mine does not have one there.

Any help is appreciated!

 

[2000StreetRod]

Idle speed?

. . . It tends to misfire when I'm at a complete stand still, above 7500 RPM's and you can't tell. I currently idle around 6000 RPM. Is that low? . . .

I assume that you mean 750 and 600 rpm. Is the 600 rpm with the transmission in park or drive? If in park that seems low to me.

According to my 2004 shop manual the pressure relief (Schrader) valve is at the forward end of the fuel rail on the driver side. I checked the 2003 salvage yard fuel rail I purchased and it has a threaded port there but no valve. Yours may just have a plug instead of a valve. Ford decided to delete the valve on the Explorers in 2004 when the fuel pressure sensor was installed. They may have done the same thing on your 2005 Aviator.

You're lucky that you have a 2005 with the improved heads. The 2003 and 2004 have poor cooling on the driver side resulting in early problems with cylinders 7 and 8. Also, the 2005 heads have 9 spark plug threads instead of 4.

You posted that you replaced the cylinder 5 plug and then checked it again and there was oil present. How many miles were on the new plug? The valve seals wear with use and can leak oil. How many miles are on the odometer? The valve seals can be replaced without removing the head. However, a special tool is required to compress the valve spring (I purchased mine for about $150) and a compressor is needed to keep the valve from dropping into the cylinder when the retainer is removed. It's a pretty big job to remove the head. If you don't remove the camshaft sprocket then timing the camshaft will be simpler. However, if the compression is low then the valves probably aren't seating/sealing and you'll need a valve job. I got an estimate of $300 labor total for a valve job on both heads that includes resurfacing the heads.

 

[BrooklynBay]

What kind of cables do you have? Are they very old? Try some Lucas engine stop leak. NGK plugs burn hot so they could fire in oil (at least this is what they claim).

 

[dmcage1]

So sorry guys. My alerts were going to my spam folder. I fixed that now. I took this to the dealer for a diagnosis and found out that I actually have a burnt valve and need to replace the cylinder head. They performed TSB 06-03-2013 - A compression test followed by a leakage test in the cylinder. Any tips for replacing the head?

I found a guy in St. Louis who will rebuild the entire head for $300 if I can pull it off.

 

[executechs]

I have a leaking intake manifold and most the coolant is going down into the coil, boot and plug #3 . I took out the Intake manifold today, cleaned it and checked for cracks on my 03 Explorer 4.6l 2 valve. I'm hoping it's only the intake gaskets (Ugly in there)

While I'm doing a timing chain job (what a mess) on this I did not get the cam holding tool, Crank positioning tool.

Can someone tell me where I can get the timing chain service set or indivisual tools to do this job and what are the best gaskets to use for this vehicle.

Thanks

 

[dmcage1]

I got the special tools by renting them from the local auto parts store (O'Reilly here) and got the timing chain gaskets, valve gaskets off of Amazon...