2004 XC90 T5 AWD

francisp · Post by **francisp** » 07 Jul 2014, 19:48

Sudden rough idling and eventual CEL coming on. XC90 T5 AWD with 162,500 miles. Just had oil changed in the last 24 hours, air filter replaced, shot some seafoam into tank and filled w/ 93 octane. Been very gentle with it since I got it 3 or so days ago. Even put new tires on it. Now I'm just stumped and worried it could be a major repair. Some thoughts and insight would be appreciated. Many Thanks!

Post by **kahl** » 07 Jul 2014, 20:10

Francis, I think your front muffler bearings are shot. I think you can get a serviceable set for about $1200.00. The costly part will be pulling your engine.

could'nt resist pulling your chain. Just get the CEL code and we can get your Vol on it's feet. also post your XC90 in the XC90 forum. Text me the code and I will get back to you tomorrow evening.

Post by **cn90** » 08 Jul 2014, 09:08

1+,

Always get the codes read first!

amcmeans · Post by **amcmeans** » 08 Jul 2014, 12:20

SeaFoam strikes again!
Check plugs....prefer OEM or Bosch/NGK iridium and replace fuel filter.
My guess is a misfire/dead ignition coil.

francisp · Post by **francisp** » 09 Jul 2014, 22:10

@AMCMEANS you got the misfire guess right on. KAHL and I got to it just in time and I am running smoothly and idling quietly once again. Thank you!

francisp · Post by **francisp** » 05 Feb 2015, 17:17

So, after 7 months and 8K miles later the CEL is back on again. I had the codes read and it pulled one, P0420 , something about the efficiency threshold of either the CAT or one of the ignition coils on bank 1 ?

Post by **jimmy57** » 06 Feb 2015, 07:52

That is catalyst efficiency code. Means the engine computer has detected the catalytic converter is not performing as it should based on reading the rear oxygen sensor. With high miles it could be the catalytic converter but many (I'd say most) Volvo catalytic converters go well past 200K miles.

Worn spark plugs can cause incomplete combustion leading to this. Front or rear oxygen problems can cause. Lots of short trips and idling with no longer highway runs can cause it.

Does the engine run smoothly and with normal power?

francisp · Post by **francisp** » 07 Feb 2015, 21:14

I have to admit, it is in need of other repairs. At 170k, it requires new front struts and rear shocks and now I think the engine mounts are shot. Engine runs smoothly when in neutral but once engaged into drive, it feels rough. I had one ignition coil replaced due to very rough idling shortly after I bought it last July. It was most likely neglected by the former owners as I have discovered since inspecting it from the bottom up. The alarm/security system needs servicing and a few other problems crop up every once in awhile. The sale price was too good to pass up at under 3k and it was a chance for me to own an AWD SUV that I've always wanted.