I got this truck a few months ago. Thought the cats were plugged because it ran like crap. Took it to muffler shop they said cats were fine because the truck would rev up just fine sitting there.

Put STP (I think) fuel injector cleaner in there and it made a check engine light come on. Ran it until I needed gas again so it could do it's job. Got gas but still ran bad. CEL went off.

Ran a lot of seafoam through it. Again, check engine light came on. Swapped coil packs around. Misfire followed coil. I filled up and cel went off. I put a few junkyard coils on and it seemed like the truck was cured.

I was just out of town for 7 weeks and the truck sat. Started good and was running great. Best it ever did in the short time I owned it. Got low on gas and put some in. Immediately it started cutting out agin just like it was before, not quite as bad. I thought bad gas. I put a red bottle of heat in it with fuel injector cleaner. It got at least 50% better, but not as good as it was.

Same thing again when I refueled. Started cutting out. So I put 2 bottles of heat in. Again, 50% better.

I need to mention this only starts cutting out when the truck warms up.

So I've just been running it thinking I need to just change all the coils. Seems like one is getting hot and causing the problem.

Today someone said the heat may be boosting the octane. So I had 3/4 off a tank in it. I put in 3.75 gal of 93 octane. I got 2 blocks from the station and the cel came on and the truck started running worse.

It seems like the additives are making the coils show their weakness. All I know to do is change that coil and see if it fixes it. I guess I should go ahead and fill up with 87 too.

You guys got any ideas.

 

Nevermind.

 

Never mind? I guess you read what the code was in the title.

 

Change the spark plugs and coils if the truck has any more than 100,000 miles on it. Use Ford or Motorcraft ONLY.
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I did change the plugs and used motorcraft.

So do you agree with coils then? Is there any kind of sensor, or something to do with a choke that could be causing this?

147,xxx miles

 

Without putting hands on it's hard to say but the coils don't last forever. With your mileage it would be the first thing I replaced.

Double check the plugs while you have the coils out, it's super easy to crack the ceramic insulators installing them and that will also cause a missfire.
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Has anyone bought coils from rock auto.

They have what is supposed to be Motorcraft for $32. Seems almost to good to be true,,,,lol. You know what they say.