2004 XC70 Rough Idle -help!

**regina** · 01-13-2010, 03:44 AM

Hello -

I just bought a (very clean) 2004 XC70 with 75K on it.

The idle is pretty rough; but the rest of the ride is extremely smooth.

I have an extended warranty, (and the dealership are "diagnostic test" people - ugh) I can't get an answer and they seem to think this is a normal function of AWD.

I was hoping for some suggestions that I could ask them to look into?

Thank you kindly,
Regina

**martinperry** · 01-13-2010, 04:47 AM

It has NOTHING to do with the AWD - Im no expert, but would be inclined towards MAF, ETM etc - the dealership should be able to pull the DTCs and diagnose from there.

**regina** · 01-13-2010, 05:01 AM

hi martinperry,

I'm very nervous and wondering if I've made a terrible mistake (and as such, should return the car for refund today at latest.) I'll look up the initials you've written and try and understand what that all means.

**martinperry** · 01-13-2010, 05:38 AM

AWD = All wheel drive
MAF = Mass air flow meter
ETM = Electronic throttle module
DTC = Diagnostic trouble code
Sorry for all the TLAs (three letter acronysms!!!)
I wouldnt panic - a decent dealer should be able to sort this e

asily, and the XC is a great car.

**regina** · 01-13-2010, 07:08 AM

Thanks again.

I'm at the dealership, and they said the same things you did... so, hopefully,
I will be able to keep this car! I really, really love it... it reminds me (in handling) of my old stickshift 245 (rip)

**Aviator** · 01-13-2010, 04:08 PM

it reminds me (in handling) of my old stickshift 245 (rip)

Better get your steering and suspension checked while you're in there, then!!!

Dave.

**gonzomech** · 01-16-2010, 07:59 PM

i have a 2002 v70xc w/167k miles...i have had vibration and rough idle issues recently. there are a number of things that could be wrong...first off has your car thrown a check engine light and diagnostic codes? if so that would be a place to start. mine hasn't through any codes...issues i have found poking around myself have been:

1. all five ignitiion coils cracked...replaced them
2. failed upper, front, torque, and side motor mounts...replaced them all...1 left to go
3. cracked spark plug...replaced all 5
4. did a throttle body cleaning service
5. cleaned/replaced pcv system
6. 2 new front drive axles
7. new boost pressure valve and map sensor
8. new inner tie rods

as things where changed vibration moved/changed...still working on this...suspect bad prop shaft. the vibration did improve after the throttle body clean and pcv system service. regarding the rough idle, what seemed to fix it was the throttle body clean and pcv system service. however, i just did it and need to see if it comes back...i did disconnect the battery which resets the ecm; ecm needs to re-learn my car/the way i drive it.

please remember my car has allot more miles than yours and is older...i plan on keeping the car for many more miles. hope i didn't frighten you...good luck and enjoy your car...i love mine.

**kamiar** · 01-16-2010, 08:51 PM

Originally Posted by gonzomech

i have a 2002 v70xc w/167k miles...i have had vibration and rough idle issues recently. there are a number of things that could be wrong...first off has your car thrown a check engine light and diagnostic codes? if so that would be a place to start. mine hasn't through any codes...issues i have found poking around myself have been:

1. all five ignitiion coils cracked...replaced them
2. failed upper, front, torque, and side motor mounts...replaced them all...1 left to go
3. cracked spark plug...replaced all 5
4. did a throttle body cleaning service
5. cleaned/replaced pcv system
6. 2 new front drive axles
7. new boost pressure valve and map sensor
8. new inner tie rods

as things where changed vibration moved/changed...still working on this...suspect bad prop shaft. the vibration did improve after the throttle body clean and pcv system service. regarding the rough idle, what seemed to fix it was the throttle body clean and pcv system service. however, i just did it and need to see if it comes back...i did disconnect the battery which resets the ecm; ecm needs to re-learn my car/the way i drive it.

please remember my car has allot more miles than yours and is older...i plan on keeping the car for many more miles. hope i didn't frighten you...good luck and enjoy your car...i love mine.

How difficult was removing the throttle body? do you have any instructions?

**gonzomech** · 01-17-2010, 06:02 AM

depends on what your doing...since i was doing the pcv system just left the throttle body bolted onto the intake manifold and dealt with it on the bench. if your doing just the throttle body clean then it will be more difficult to remove/install...you will be working blind and at weird angles allot of the time!

the hardest thing was to get the banjo nut into the manifold...got it threaded at what seemed to be the 500th time! the actual cleaning is about 1/2 hour of scrubbing w/cleaner H (bought at dealership)...using a rag and nylon toothbrush.

there are a couple of instructions on this forum on what to do. what the instructions didn't tell me is that:

1. for more room to work remove the radiator fan assy..
2. have a torque wrench that can do in*lbs....10NM or 88.5in*lbs. is what is needed for the 4 bolts...at least on mine.
3. when cleaning orient the tb so that the electronics point up...don't want to get flowing cleaner down the shaft that goes into this end of the unit.
4. make note of the orientation on the manifold...if 180 degrees out you will be buying another gasket.

have fun!