lexrex

Friend's 2006 5.4L was throwing misfire code for 3 cylinders and occasional flashing CEL and some power loss. They were 1000 miles from home so drove it home. Cat was fried and changed by mechanic. Misfire cylinder 1 came back same day.

I have an 06 F250 sitting in my carport that needs the timing 'fix' (guides, chain, phaser etc.) I have the Ford parts, just need to do it. Anyway, I'm familiar with this issue my 5.4 has the classic symptoms, including oil pressure that drops to near zero when warm (I installed the oil filter adapter that accommodates transducer, very worthwhile.)

However, this vehicle has a knock/tap only in the 2000 - 2100 RPM range. We used a stethoscope on the oil pan (no knock), the timing chain covers (no knock). Then since it's an E350, we took the interior engine cover off and realized the knock is heard loudest inside the intake manifold. It's way too loud to be injector noise.

So, given the unusual knock characteristics (especially only between 2000-2100 rpm!) and the CEL activity, what are the potential causes? I'm really stumped by a top-end noise that only occurs during a small RPM range ...




Appreciate your replies.

Summers22

iTrader: (2)

If the cat was fried, look at faulty injectors. Maybe #1 has an issue. Was the cat that was fried on the passenger side?

JimmyB1232

Does it happen at that rpm range at certain a speed/gear? Or just anytime you get in that rpm range? Does it happen if you rev it up in park or neutral?

techrep

iTrader: (1)

flashing CEL is a mis-fire condition.. when were the plugs changed last.. maybe hearing the IMRC moving in the top end

lexrex

I'll have to ask my friend, will get back.

lexrex

I've heard it in neutral, very consistent. It also happens when driving but I'll have to ask the owner.

lexrex

yeah, know about the misfire/flashing connection. Will ask about the plugs. Can the IMRC really be that loud?

lexrex

I just added, to the original post, a recording of the noise.

michael@flesner.com

Any update? Ford had no luck diagnosing.

techrep

iTrader: (1)

That was 4 years ago buddy...