Started missing a few days ago.
When I bought the truck(used) about 9 years ago it was missing and needed 3 coils.(nephew not very good with repairing).
I fixed them after going to the dealer and had them read it on their computer.
Is there any way to tell if a coils gone bad without going to the dealer?

Thanks,J

 

Try disconnecting one coil at a time (thru electrical connector) and run the engine . Removal of each good coil will make the idling worse . If you run into a coil that does not make any difference , that could be the culprit.

With this test , it could be the coil or bad spark plug or coil rubber boot(cracked and arcing) . If the issue lies with injector , that will require different diagnostics.

Good luck,

 

Thanks Wolf.
I thought that's what I'd have to do.

 

That procedure will only work if you have a cylinder completely dead, a rare occurrence.

If it's a mild or intermittent misfire, you have to read the misfire counts in Mode $06 for clues as to which cylinder(s) has/have the misfire(s).

 

I have a code reader would that show on it?
The check engine light hasn't come on?
Thanks. The code mode $06 can you explain?
Thanks, J

 

No, a misfire will generally not throw a CEL with these engines.

Depending on the severity of a misfire, your code reader may or may not read it.

The $06 mode can be read with a Bluetooth OBDII port adaptor such as , used in conjunction with the Torque app available for your smart phone.

I am sure there are other ways to read this test result, but I do not know what they are. On a side note, I have that adapter from the link above and it works well.

 

Only use Motorcraft parts like your hood sticker says.

Change the sparkplugs and note any cylinder holes that have oil or coolant in them. If that issue is not fixed new coils will soon fail. If all are dry at the least replace the boots. At that point if you have to pay someone with a scanner good enough to read mode $06 then you maybe ahead by just replacing the coils. Yours and others time is valuable and the coils wear out at some point anyway as you have already seen with the three replaced.