I recently purchased a 2004 c70 with 89k miles. After a week of driving my girl alerts me to a check engine light and extremely rough idle at stop and at all speeds. Parts store code reader pointed to cylinder 3 misfire. Replacement of said plug and coil pack produced immediate positive results. I see alot of people posting questions and problems but sadly not many post back about the fix. Since repair manuals are basically nonexistent i thought this may at least spread some knowledge

 

Remember all the plugs & the coil paks are the same age, probably. Fuel economy & performance might be improved by replacing them all!

 

Agreed. While i was in there i noticed that one had already been replaced. So yes 3 are still factory. Also the one plug from #3 has a short, needle like tip. Is this the way some plugs are made? Or was the tip likely burnt out?

 

Probably a high arc burnt tip.

 

Thanks for your replies master sarge. Once it warms here in the south im gonna go over this car with a fine tooth comb and get everything right...rest of the plugs, coil paks, heater core and antenna issue

 

I have a 2001 S40. I have replace wires, plugs, and a bad coil in #3.
I have a rough idle and it has codes for misfire in 3 and 4. p0303, p0304. Any suggestions?

 

Did you replace the COP & plug for #3 & #4 cylinder?

 

It is likely a iridium plug.

 

Volvo OEM plugs have the same tip.