Hello,

I recently got a 2007 Volvo XC70, love to car so far. However today when i was on my lunch break my check engine light came on and i took it to autozone to do a scan. It came up with P0304, Stating cylinder 4 is misfiring. I went and bought a replacement sparkplug and ignition coil for the car and replaced it myself. I made the assumption that the 4th sparkplug from the left, when facing the engine with the hood open, was the 4th cylinder. Left of the hose going over the engine cover.

I guess my main question is, is this the correct sparkplug socket for cylinder 4? the check engine light is still on, the misfiring is occurring as bad but still a little sputtery during idle. I took it to a different autozone (closer to home) and did the same scan and it came back with a few extra codes that the other scan didnt read. Any suggestions?

 

Posting the other codes, maybe? From your post it sounds like you just replaced one spark pulg... is this correct or did you replace them all? Did you check the gap on spark plugs coming out and the plug/s going in? Was there any fouling on the spark pulg/s you did replace?

Sorry if I seem rough in my reply, had a rough day at work and probably too many beers in me to care...

 

P0300
P0304
P0442
P0204

Yes i only changed 1 spark plug and coil. Was hoping itd hold me over till friday :P but it didnt resolve the issue like i hoped.

I took it to another autozone and then saw P0305 after the spark plug change
I asked them if they could reset the codes so i could see if anything changed but they said they couldnt.

I used the recommended part from autozone for the spark plug which ill link
NGK IX Iridium/Spark Plug 6418- ReadReviews onNGK IX Iridium #6418

 

P0300 - general misfire, cylinder not detected.
P0304 - cylinder 4 missfire.
P0442 - Evaporative Emission Control System Leak Detected (small leak)
P0204 - Cylinder 4 Injector Circuit Malfunction

The ecu expects that everything is the same for all cylinders (plugs, wires, injectors) and that they will react the same. If you have put Iridium plugs into a system that has copper plugs stuff will get more effed up... ignition systems are one of the few that exact manufacturer replacement parts are essential and that all parts are identical. Just because Autozones computer says they are the same or better (total myth, go with oem recommend copper over Iridium or whatever) they are not.

You would be best to replace the new plug and wire with the old one (make sure the gap is correct, if you have it) and replace them all when time/money is available. Make sure you have a torque whrech and the torque is correct. Make sure the gap is correct on the new plugs...

If your not sure what you're doing or don't have the tools, take it to someone that does and let them know what you want and what you have done. It may cost more but can save you on replacing an engine or car.

 

OK, so i went ahead and bought 5 Bosch OE Fine Wire Platinum Spark Plugs part number 6730. they are pregapped at .028, I am going to replace all 5 sparkplugs and put the old volvo ignition coil back on the vehicle that i replaced yesterday.

I am concerned though after doing further reading that the cylinder 4 fuel injector may be the actual problem that lead to the misfiring. Would it be a good idea to spend some money on fuel injection cleaner before trying to take it to a mechanic to service the fuel injectors?

 

No, the code you have there is for the circuit. What causes that code is the injector is unplugged, a wire breaks, that sort of thing.

 

Ah OK thanks for that information.

Edit: Im going to change the spark plugs in about 2 hours, ill let you guys know how it goes.

 

OK so i changed the spark plugs and the old ones looked pretty bad. I placed the new spark plugs and then drove it for a bit. The slight loss of power i noticed the other day is gone. However, i still have a little sputter going on. Im not sure why.

I went to two different places to have my OBD codes scanned. Both places came up with no codes after trying. I think i may have fixed the misfire issue i had earlier. But why would the sputter be happening still.

I checked the oil and its at the 2-3rd row of x's on the dip stick. Only 1 row didnt have oil present.

I filled the rest of the tank (half) with premium and put lucas injection cleaner in there just to clean it up a little. I just got the car about a week ago and i think its been sitting on the lot closed to empty for a while.

Also my CEL is still on but the OBD scanners came up with nothing? Could there still be a potential problem that the scanner cannot read, or would it be able to pickup why the CEL is on anyways. Do the volvo CEL reset or do i need to disconnect the battery and see if they pop back up?

Thanks everyone for the help, sorry for all the questions haha

Edit - I forgot to mention. When i go about 45-50 mph i get some sputtering while driving or some sort of engine shaking. This has not occured until the CEL issue started occurring. When i first turn the car on i feel the sputter but when i get back from driving and park the sputter is not nearly as noticeable but slightly present.

 

Any status update on your new rig with the ignition coil concern/code?
I know that if you move the coil to another cylinder and check the codes thereafter, and that cylinder throws the code, the coil is the problem.
So, if you still have the new coil, it might be worth moving old around to diagnose.

 

It ended up being cylinder 4 spark plug wasnt tightened down enough because i didnt removed the tube going over the 4th cylinder spark plug when changing it.

Once it was properly torqued it worked properly.

I felt really nooby afterwards. Shes driving like a beast again.

 

Mine is starting to have rough cold starts and has, what seems like, a mis-fire between shifting gears on the road.
I recently replaced all plugs and am wondering whether it's the fuel filter, choking the EFI or I gapped the plugs wrong.
I put opened it up to .3 since the range is 0.28-0.32 but am wondering if I had the wrong gap at .32 by mistake and she doesn't like it. I read that the turbo likes a smaller gap plug.