06 expedition, stumble, almost dies

[a_kelley]

Ok so I've got a 06 expedition 5.4

No codes other than misfire.

Fuel is good gasoline, no water.

Fuel pressure/volume good. (Delivered 2.5 gallons in 2 minutes!)

New plugs/coils.

Timing good. Just did chains/phasers.

Hard hard stumble almost dies when given wide open throttle, even in neutral. Misses on cyl 1234. Sounds good at idle. No exhaust gas in coolant.

Removed upstream o2 (plugged cat?) But, No change. Unplugged MAF, no change.

Fuel trims @ 0% on Bank 1.. bank 2 11% (don't recall +/-)

Ideas? I'm fed up with it. Compression test & leak down my next step I guess.

 

[a_kelley]

A tech friend suggested that the o2 hole is too small to let it breathe if the converter is stopped up, so will disconnect the cat at the manifold tomorrow, and see what happened.

 

[a_kelley]

 

[a_kelley]

After that, I had to reset KAM because it was behaving the same way!

 

[a_kelley]

Oh that was the burning smell. I forgot to pull the label off the pipe.

 

[C.Berry]

So replacing cat and reset fixed it for ya?

 

[a_kelley]

Yeah, after fixing the cause (screwed up cam timing)