98 XC70 P0410 only and possible misfire

flagracer · Post by **flagracer** » 26 Jul 2014, 20:51

Hey folks

My sister's 98 XC70 started throwing the P0410 code a few months ago, and I understand about the air pump and relay etc. All the posts say it should not affect driveability. The problem is, it's the only code that ever comes up, and the car feels like it has a slight misfire. It has plenty of pep, but you can always feel it. Had her run a can of seafoam through the gas earlier in the week, no change. Does whatever clogs the injectors on these not dissolve? She's had it one year so I did a tune up, NGK double platinum plugs (couldn't wait for volvo as I had to drive a an hour to get to her) cap, rotor, air filter, wires looked fairly new, no oil soaking, arcing etc. It made a slight difference, but the feeling is still there. In the absence of any other codes, I'm just curious if there is any particular area that should be closely checked on the 2.4 turbo engine. The turbo itself seems good, a little oil in the tube, but better than any other volvo turbo I've worked on (the neighbors have 2 V70s). I forgot to clean the MAF while I was at it, but it's on my list. 140k, timing belt was done last year, plugs had powdery build up, one had some oil tube leakage, but not severe. Thanks for any insights.

Post by **rspi** » 27 Jul 2014, 02:04

Rough idling is usually a problem with a vacuum leak. I mean you need to pull all of the turbo intake tubing out and inspect them for cuts, tears, hokes, etc..

Is the PCV system in good condition?

Also, if the car is not running smooth I would bite the bullet and go with OEM ignition parts all the way.

flagracer · Post by **flagracer** » 27 Jul 2014, 03:16

ok I am aware of the quirky pcv system. When I pulled the beauty cover there was some oil pooling in the recesses right around the hose so I'm sure it's due. That can cause some issues? The main turbo hoses were good. What seems like a miss is rhythmic, like it's specific to one cylinder, not a general vacuum leak with a random effect.

Post by **abscate** » 27 Jul 2014, 04:27

The turbo cars are finicky with plugs; many here recommend only single electrode volvo plugs for turbos. A vacuum leak can give you a pretty regular miss, too, in these cars.

Post by **rspi** » 27 Jul 2014, 06:23

If you don't have a code, I seriously doubt you have a miss. These cars LOVE tossing codes for everything except low fuel pressure.