Misfired on number 3

[Teresa]

My 05 expedition..is misfiring..we place all plugs..coil pks..still getting reading number 3..is it possible new plug bad? Any ideas...thanks

 

[Bedrck47]

Welcome to the Forum

 

[Bedrck47]

Did you also replace the coil packs and boots with new parts

I doubt that you have a bad new plug although its possible.

I would first check the wiring to the coil and injector make sure the connectors are clean and tight.

If that isn't the problem I would then swap the coil, boot and plug with the #2 cyl and see if the misfire changes to #2

 

[USMCBuckWild]

possible. try swapping plug and coil to another cylinder.

if problem follows, its one of those.

if problem persists i would look at injector, then leakdown test. leakdown will help identify lazy lash adjuster, bad rocker, worn cam lobe, etc.

 

[Teresa]

Thanks replace all coil pks..plus replaces the plugs...thinking its the fuel injector..so that next...

 

[Darkspartan]

On my 2003 Expedition Triton 5.4. I changed all 8 cop and went to densel iridium plugs. Ran great 3000 miles. Changed right cats and swapped muffler with 14" glass pack, ran great for another 1000. Then had lean bank and miss for cylinder 123, changed all o2 sensors which are all showing less than 1.000 reset pcm and lean and miss on 1&3 again. changed cop and plug on 1&2, reset and still missing on 1&3 and lean code.
Can anyone help going broke and out of ideas.

 

[docraymund]

Did you replace the cop rubber boot too?

 

[Darkspartan]

Yes, the whole coil pack

 

[docraymund]

You didnt check the fuel pressure?

 

[Darkspartan]

I didn't. will try and see if fuel comes from fpr tube.