Cylinder 5 misfire even with new coil !

OK guys, need some help here. 2007 Expo EL, 105K miles... I would say Very good condition ... if that matters. This morning check engine light came on... went to autozone.. code PO305 #5 misfire... OK, easy right.. change coil pack (#5 is the drivers forward most plug right?), purge codes... comes right back on same code. Drove it yesterday, ran well. now that light is on it is running rough... so I am assuming its not a one time misfire

Seems oddly coincidental to me as in the past month (about 200 miles ago... 3rd vehicle we rarely use) I had the plugs changed by a mechanic (for 100K mile service), and Tuesday inspection was done and obviously no codes showed then.

So, if its not the coil pack, what else would I be looking for ? wiring is all pristine (this is a 100K mi truck that could pass for new)

Thinking of removing the spark plug to check it... but I have heard these can be a bear. what size wrench are they and they seem real deep in the hole... are they easy to get back in?

First try with the truck running, to wiggle the wire going to the #5 coil to see if you can get it to misfire.

Yes, check the spark plug easy to do especially if you already had the coil out. (spark plug socket and a extension you will be good to go)

If all that checks out change coil packs with the one next to it. run that for a while and see what happens.

Just a couple of thing that are easy to do and don't cost you nothing
If this doesn't find the problem at least this will eliminate a lot of things and get you closer to the problem.

Thanks, Its a new coil pack but I can easily change it with one next to it to test.

pennyanguy said:

Thanks, Its a new coil pack but I can easily change it with one next to it to test.

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Sometimes these electronic parts are bad brand new no matter what brand you get it just happens. (had it happen to me) I spent a lot of time searching for the problem for nothing. Switching will just eliminate that.

Usually I would have done this before I bought the new one. More diagnosing and less throwing parts at it makes your wallet happy.

I agree, did not even think about switching them while I was standing at the parts counter... my bad. Thanks for the input though

For me the CEL kept flashing and giving me a pending code for #5 misfire, the mistake I made was the new coil pack was not firmly or tightly fixed in place, the small bolt was stripped. I added a few washers to the bolt and it helped secure it in place. But, I had damaged the new coil pack when it was loose and I had to put an old coil pack I had as a spare.

OK, I will check that... thank you

Msport said:

For me the CEL kept flashing and giving me a pending code for #5 misfire, the mistake I made was the new coil pack was not firmly or tightly fixed in place, the small bolt was stripped. I added a few washers to the bolt and it helped secure it in place. But, I had damaged the new coil pack when it was loose and I had to put an old coil pack I had as a spare.

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why do you call it a pack?

07navi said:

why am I such a pack?

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You spelled Hack wrong.

Yupster Dog said:

You spelled Hack wrong.

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jerk