Wife's car started having constant misfires on #4. I pulled the plugs on 3 and four and not only they looked like crap the gap was 60mil and spec is either 28 or 40 depending on the brand of one ground plugs.
Those plugs have less than 25,000 miles yikes!
I cleaned the plugs and swapped 3&4 plugs and coils and the car ran great before it didn't: "somebody" forgot to plug the MAF back in. (Me).
Plugged that back in and engine ran great (instantly the idle corrected)
I reset the codes and replaced all plugs with some NGK quad platinum like the car came with and ran fine for 110,000 miles yeesh.
Since all the plugs were about the same level of crappy I suspect the #4 coil just isn't quite as strong so I swapped it with 3 just to see if the problem returns it moves to cyl. 3 and I can confidently call it the coil.
Kudos to the wife she noticed the misfires before it tripped the ses/mil
Now for a good test drive maybe I'll take to Chicago tomorrow. Wife is gun-shy she had to drive the last 20 minutes in fail safe yesterday was not a fan.
Notice the resistor color codes on the coil packs. i wanted to keep track of the original locations.
Oh: a few tips on plugs:
They were so stiff to remove I out copper anti-seize on the threads and torqued to 30 Nm. The original spec said 25 but there was plenty of compression left in the crush washer the last 5 and I read they re-did the spec to 30.
Number six is a bitxh to get the socket on/in/off/out. I use a DeWalt 90° right angle drill adapter for most small bolts/nuts under the hood and it worked great for turning out and in the sockets (on hand tight mode).
The plug socket held the plug too tight and pulled the socket off the extension. I took the rubber grip out and cut three slits 120° apart to reduce the grip and now it works far far better. I can get a new plug into the socket without a pliers and I have some hope of pulling the socket out with the extension.
I have a locking 3/8" impact adapter which I used to "hand tight" the plugs but then I used a digital torque adapter to set the torque for the sockets and the coil packs
