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Discussion Starter · #1 ·
I have a 2006 xc90 V8 around 90K miles. I replaced the plugs at 80K.

Earlier this week I started having a significant misfire with lots of messages on the dash. I ran my VIDA on the car and got the P03000 random misfire and a code for 5 of 8 cylinders. I reset the codes and ran the car again and only got a code on #2. Swapped the coil with 1 and 2 then got the code on #1 so I replaced the coil and all seems fine.

My question is how did I originally have codes for so many cylinders? Could a single bad coil caused some bad codes to show? Or is there a bigger problem that I haven't found yet.

Thanks a bunch.
Mark
 

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Discussion Starter · #3 ·
Interesting thought. I wonder why multiple coils could go bad at once. I used bosch plugs, not OEM. Has anyone had problems with non-oem plugs?
 

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have you had the valve cover gaskets replaced before the misfires..??the ground wires for the coils get broken if you are not careful...
 

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Discussion Starter · #5 ·
I haven't had the gaskets replaced. The only thing i have done recently was change the plugs about 10K miles ago.

Anyway, I have put around 150 miles on the new coil for cylinder 2 and haven't had a single code go off. So knock on wood that appears to be the problem.

Really I was curious if anyone had mis-fire codes that turned out to be faulty codes. I know on the subaru site they talk about mis-fire codes going off when you travel down a really rough road, that can cause mis-reads at the crankshaft sensors. Didn't know if a single misfiring cylinder could do the same thing (especially since my wife drove it for about an hour in stop and go traffic).
 

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Volvo S80 V8 Misfires

have you had the valve cover gaskets replaced before the misfires..??the ground wires for the coils get broken if you are not careful...
Hi cbv1... I had replaced the valve cover gasket before the misfires... but i didn't get where are the ground wires get broken from...few days now gone and my car not yet repaired...hopefully get advise from you...thanks
 

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I would give the coil wires a thorough check at the misfiring cylinders, the wires get very very brittle from the heat under the engine covers and unless you were very very cautious when removing the coil connectors it's likely that the connector wires or perhaps the ground wires for each bank is no longer making contact. I had to repair several wireless that looked good but were broken internally on my last VC and plug service
 

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I had vc gaskets changed on my v8 then got missfire code. Took back to volvo and discovered loose ground now have code for cat bank 2. Could mechanics failure to connect ground cause cat to go bad because of missfire

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when removing the valve cover nuts that have the ground conections you must counterhold the bottom nut with a very thin wrench,if you dont you will break the ground wires for the ignition coils...
 

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V8 Misfire on XC90

have you had the valve cover gaskets replaced before the misfires..??the ground wires for the coils get broken if you are not careful...
Recently had my Valve cover gaskets replaced - maybe 2 months ago.

V8 just started to develop a misfire - comes in at about 1400 RPM to 1600 RPM and feels like a stutter or grinding.
I can accelerate past it.... but it's getting worse.

I took the step of cleaning the Throttle Body earlier today as well as the MAF sensor as I'd seen that on this forum - unfortunately no change.

Have you got any pictures of the Coil wiring and how I get to them to check?
Could it be anything else but this seems like its exactly what has happened.
 
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