97 Thunderbird 4.6 missing/rough running fixed

[chestand]

Sunday, I exit the highway and at the next stop sign, the car was chugging and missing. It was a coil pack. In 97, Ford was using two coil packs - with two coils in each pack. Each coil fired two cylinders - one on the compression stroke and the companion cylinder (waste spark) on the exhaust stroke. So, when a coil in one of the packs goes, you have a miss in two cylinders. The V8 instantly becomes a V6. The removal/install process took all of 5 minutes, just remember to mark plug wire location on the pack before removal. Four 7mm bolts and it's smooth again.

Just passing on my experience. Maybe it will help somebody else.

 

[The_Jed]

I would assume the others are on their way out as well. Might want to replace them as a preventive measure.

Congrats on the quick fix!

 

[Rand]

There is only 2 and failure of one doesn't mean the other is going to fail.

You might want to check your plug and wire condition though.

 

[JDW]

Surprised one failed , Two birds here with the 4.6 and a few friends as well we have never had one to fail. Glad to hear you got her right

 

[chestand]

It's funny though. Neither the primary nor secondary side of the pack tested bad when I used an ohmmeter on it. I resorted to disconnecting the primary connector on each pack while the engine was running and replacing the one that had the least effect on idle when disconnected.

It is possible for a coil to check good but still fail in use.

Plug wires are next (OEM). Plugs look to be a major PITA on this motor though. It's my dad's car and I suspect they're OEM as well.

 

[bdcardinal]

Originally Posted By: chestand
It's funny though. Neither the primary nor secondary side of the pack tested bad when I used an ohmmeter on it. I resorted to disconnecting the primary connector on each pack while the engine was running and replacing the one that had the least effect on idle when disconnected.

It is possible for a coil to check good but still fail in use.

Plug wires are next (OEM). Plugs look to be a major PITA on this motor though. It's my dad's car and I suspect they're OEM as well.


Nah, plugs on a 2V are easy peasy. Usually when you replace one of those packs, it is best to do both. The new plugs might look different than the ones that come out, they will most likely have the full length threads to prevent blowout.

 

[Black_Thunder]

i have a 97 t-bird myself, never had a coil issue yet but i've changed the plugs and wires.

the plugs are fairly simple.

about the only thing i had to remove to make things easier was the intake tube.


the wires aren't too difficult but they run all over the place from side to side, just make sure you route them the same way.

I only use motorcraft plugs and wires on my modular V8's

 

[MuzzleFlash40]

Never had an issue on the 96 Cougar I had years ago. I did put MSD packs on it when I put a set of P.I. heads on.

 

[artificialist]

I have been told that as an ignition coil expands when hot, and if one wire is marginal, it may cause an open circuit only when hot.