Rough Idle 2004 XC90 T6

[KenMacksey]

Having a problem with a 2004 XC90 T6. Took it to the nearest Volvo dealer
3.5 hr drive away and spent $1500.00 and they still don't know what the problem is.

Runs very rough at idle but ok at higher speeds. Check engine light comes on and produces codes P0300 - multiple cylinder misfires, code P0301, 0303 and 0302 - Misfires on cylinders 1, 3 and 2. Also code P0130 - O2 sensor bank 1

Any info on most probable cause greatly appreciated.

Thanks

Ken

[songzunhuang]

Ken, this is almost spooky how similar it sounds to my problem in my 1998 V70 T5. Here's the thread on that https://www.matthewsvolvosite.com/forums ... &sk=t&sd=a

It throws misfire codes on EVERY cylinder as well as the P0300 random misfire code.

Unfortunately, I haven't been able to track it down despite trips to 2 dealers. They keep telling me to change things and it keeps failing. So I am trying to track it down myself now with the help of people on the forum.

I hope you can figure this out and that somehow, it'll be the same thing for me. Good luck to you. I'll let you know if I discover anything. The vacuum hoses are the next thing I am attacking.

[tballjohn]

I had similar issues with my 2003 XC90 T-6. I went to a local independent and it took some time by them (and a few days in the shop) but the issues is gone (for now). I had the misfire codes on two banks. replaced the plugs to no avail. Then replaced the coils, still no luck. After searching, my mechanic found a tech bulletin that had one last resort before replacements and a rebuild. It has been a while, so all you true Volvo mechanics, please bear with me and correct whatever I may misquote. I think the bulletin was referencing the lifter guides might be either bent or gummed up. The last resort was to flush and clean with oil at high rpm's. He did this and had to change the plugs one more time. But it worked. He wasn't sure how long the fix would last (2 days or until whenever), but it has been about 4 months now and al lis well (except I just got a code that the MAF is out, so that is my next challenge). By the way, this is at about 105,000 miles. Quite a bit of headache, but still love the 'ol XC.

[DjCalvin]

So My T6 is doing the EXACT same thing @ 127k
I brought it to our volvo dealership this week and they Gave me a list 2 pages long of what they wanted to do:
Replace plugs (ok, I have them anyways)
Replace all Coil Packs (I replaced them all last year when one went, I will check for arcs though)
Replace Camshaft Sensor (no code for this though.. DTC is not active)
Replace Air intake tubes (had a crack in it.. I had them do this @ $360)

And after all that.. they said it still may be there. and $1500 later...

I mentioned this thread and the TSB regarding lifters and the Shop Manager looked at me like I had Two heads... Any more info on this TSB? I know its 4 Years Old, but I'm hoping someone else has run across this.
Thanks
C

[songzunhuang]

Hey, I forgot to update here. I was able to fix my problem. It turned out that the plug wire from the coil to the distributor was disintegrated inside. There was no way to tell from a visual inspection. I only discovered this on accident when I ordered a new coil kit (MSD) and it happened to come with a new wire. As I was pulling off my original wire, it came apart and I noticed that the inside of the boot and the attaching wire was completely gone.

So, I'd recommend a quick check of that wire. You can get a replacement for around $20 and it's an easy fix - just change the wire. If you are getting multiple misfire codes on different cylinders, the wire would be my prime culprit.

[DjCalvin]

Thank you. I just ordered new plugs for the hell of it (time to change them anyways) I'll update after I take a look at the coil packs tomorrow.

[boosted5cyl]

Very little in this issue from the '98 T5 translates to the T6, very different setups.....
The T6 is a Coil on Plug design and doesn't have have single coil lead like the older P80 cars.
My first suspect would be a vacuum leak. This will make the car idle rough, multi cylinder misfires and throw an O2 sensor code. A failing MAF can also cause similar symptoms, even if a code doesnt exist. With the car turned off, disconnect the MAF, then start it up and see if there is any change.

Plugs are worth a try, change them, clear the codes and go from there. With a muli cyinder misfire, I would hold off on the coils for now.


...Edit all of the codes are on bank #1. Focus there. Forget the MAF. I wonder if you have an intake manifold leak? I think the fuel trims on that bank might give you some clues. You need to find someone who can/will actually look at the O2 sensor voltages on that bank to see if its switching and or responding correctly. I have a theory that your O2 sensor, or the wiring/connections for that bank have failed, the motor and fuel trim has gone full rich and the plugs are now black and fouled causing the misfire.

Read this:http://www.obd-codes.com/p0130

If you find that its either the sensor or wiring/electrical, go back to that shop you spend $1500 at and raise hell!

[DjCalvin]

So I replaced the following yesterday:
Camshaft Sensor - $60
Coils 4 and 5 - $120
All 6 spark Plugs $80 - Plug #5 was the one that was throwing the code last. The plug was covered in oil.
I cleaned up the ground connections on the head for the coil grounds as well.

She's purring like a kitten now.. not a single skip

And this morning I get all the symptoms of a bad CEM. Waiting for a tow truck

[boosted5cyl]

Until you get to the bottom of that O2 code issue you may keep having issues. Hope the CEM is OK, but that would explain the issues you are having.

[DjCalvin]

Never had an O2 Sensor code.

Edit: I realized you were responding to the OP, not to me. Sorry about that.