Joined: Oct 2017

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I have a 2004TL with about 200k on it and I drove car yesterday and ran perfectly. Today when I started it had rough idle and when driving def feels like dropping cylinders and has CEL. Codes are po300 thru po306 ( every cylinder misfire) . Strange to have every cyclinder with no other codes for crank sensor or something else. Not sure where to start.

Joined: Dec 2003

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From: MAGA country

Joined: Oct 2017

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Pulled console covers off and inspected ecu and looks dry and dusty. Reset codes, started it and watched live feed on scanner, hoped would see a singular cylinder misfire but got all 7;codes after a minute of two of idling.

Joined: Feb 2016

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Checking the coils and plugs might not be a bad place to start if you haven’t done that yet

I had a Civic with oil all over one of the coils due to a bad valve cover gasket. CEL said misfires on all cylinders. Haven’t had an issue with a misfire on my TL yet, though

Joined: Oct 2017

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Checked coils, not sure what readings should be but two pins measured around 1.7k ohm and all 6were close. Replaced all plugs and compression was around 150-170psi. No change.

Joined: Feb 2010

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Joined: Jul 2014

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From: GTA, Ontario

Joined: Oct 2017

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I changed plugs and did a compression test. Plugs had some wear but nothing terrible. Compression was 170 across front and about 150in back but not sure I could get fitting totally tight in backside. I didn’t try each disconnected one at a time.

Joined: Oct 2017

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I messed with car more and it ran rough enough was tough to tell change when disconnecting coil packs but when I unhoooked #6;it impacted less than others. So took a shot and got used one from “you pull it” salvage yard and replaced it and reset codes. Idles smooth and drive it about 25 miles tonight and ran great. Not sure why one bad coil would make all 6 mis fire but I am glad it’s fixed. Car ( and I assume coills)have 200k on them and may buy a compete new set of OEM. ( I don’t typically love aftermarket stuff , lotta junk out there) Thanks for all the help, this site is great resource of knowledge.

Joined: Jan 2017

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From: Maryland