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cyl misfire and coolant in the plug well

1339 Views 10 Replies 6 Participants Last post by  misterclean59
My '11 Crown vic with 270k miles suddenly started running rough mostly at the lower end of the gears. By the time you got into o/d the whole car shook. Scan tool gives me P0307 cyl 7 misfire, and P0316 misfire upon startup. So I pull the coil on 7 to find a pool of burnt smelling coolant about 2" deep. Siphoned and blew it out and removed the plug to find it's electrodes fouled with a thin coat of something shiny and black. Rubbed off without much effort. The plugs are about 4 weeks and 1500 miles old. Pulled cyl 6 coil right next to it and found a lot of white particles about half the size of rice stuck to the sides of the plug well walls. Seemed odd as I'd just blown out all the plug wells a month ago. Blew it out again and removed the plug to reveal electrodes that were coated slightly white. This plug had a ring of a black just south of the hex part. Looked like darkened sort of coagulated oil. Wiped off easily.

The car drives much better now after blowing the antifreeze out of the plug well but the miss is still there. So glad as this might buy me some time to get this figured out.

I'm not even sure how it's possible for coolant to get in a plug well. Any ideas, head gasket maybe? What's my next step in investigating?
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Removing the intake is surprisingly easy. The plastic intake on my 1997 (this happened in 2000) 4.6 grand Marquis cracked at the water crossover pipe. This scared the crap out of me because I don't work on cars much and at the time it was the first time I had worked on something with fuel injection. After consulting a friend who knew this job well I had the intake replaced in about one hour........maybe 45 minutes. The tricky part was getting air out of the system so the coolant could flow. I found that the cross over pipe on the intake was about a half inch higher than the radiator cap. I removed a plug in the cross over pipe and displaced the air with, fixed.
Have you priced it yet? I remember buying mine from the Ford dealership and it was a little less than expected.
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