sport trac 2007 missing on #3

[newguy]

Hello all
I have a shudder at 1000 rpm and 40-50km in hi gear.
it's a v8 3v
code for missing on #3

replaced all plugs
had fuel injectors cleaned
replaced the coils
compression check
problem still there??
any suggestions?
Thanks for your time

 

[EddieS'04]

Check for a cracked ceramic spark plug insulator. Also a solid clean connection of the spark plug boot to the coil. Also corrrosion free and solid connector to the coil.
Im just throwing some guesses. I own a gen1. A whole different ignition system.

 

[newguy]

Thanks for your input.

 

[EddieS'04]

I also forgot to mention. It is not imposible to get a bad new coil. You could try swaping the coil from another cylinder. If you get a mis fire code from the different cylinder. That would point to a bad coil. Electronics can be tricky even new ones.

 

[newguy]

Yes I did change them out, plugs, coils and it still misses and shudders at 1000 rm under load only. a real brain teaser so far. Thanks again Eddies'04

 

[Todd Z]

And code ??? and what Eddie was saying is take the coil from plug 3 and put it on #7.... Re test... Could have a bad fule injector...
did you change the fuel filter ??? Hows the FPDM ??? did you hook a computer to scan??

 

[newguy]

Thanks. yes I tried moving coli then plug from 3 and code was still miss fire on 3. Garage did a fuel injector clean and and tested fuel pump, all with in range. I also noticed it only happens after engine is warmed up. Starting to think because it only happens under a load in might be torque converter?.

 

[newguy]

Sorry not familiar with FODM?

 

[Todd Z]

FPDM. Fuel pump driver Module.
Common failure on the ST. It’s aluminum mounted to steel above the spare tire and it rots. Stupid ford.

there have been some issues with Valve followers wearing out on cylinder number three on the engine which causes the problem. Not noticeable on compression test. we have also seen intake manifold gasket leak. Have you checked for an upper intake manifold gasket leak??

 

[newguy]

Wow. Never thought of any of this. I really appreciate your time.
I know what I’m doing tomorrow
Thanks again