2001 Volvo T5 S60 Idles Roughly, hesitates at idle

T5S60 · Post by **T5S60** » 20 Apr 2015, 15:33

Hi, my Volvo has had a rough/hesitant idle now for a little bit and I'm kinda curious what could be causing it. Another thing I noticed is when its doing its intermittent/rough idle the dash lights actually get brighter/dim. Any Ideas what could be causing this?

I heard someone had a similar issue and he was able to fix it by replacing his mass airflow sensor. He actually diagnosed the issue by removing his MAF and running the car without it (is that safe?). I will start by seeing if I can clean the airflow sensor (with MAF specific cleaner). Any other suggestions?

Post by **jlq1387** » 20 Apr 2015, 17:07

I am having the exact problem with my 2002 S60 (non-turbo). I have put close to $2000 in repairs in the past 3 weeks, and none of the repairs have solved the problem. I have looked at several different forums on the internet, and from what I can tell this seems to be a common mystery with S60 line.

T5S60 · Post by **T5S60** » 20 Apr 2015, 20:55

Also Just realized the spark plugs have not been changed since I purchased the car at 100k miles... has 155k miles now. So that probably needs to be done ><

Post by **abscate** » 21 Apr 2015, 04:50

Pull out the plugs and take pictures, post here. The condition tells a lot about your engine condition.

The likely cause of a rough idle is a vacuum leak or split hose. Check these before throwing parts at it.

bschlage · Post by **bschlage** » 22 Apr 2015, 20:41

It could be your throttle control module. There was a recall on them so you'd get it replaced for free if it hasn't been already. I'd check that out before you spend anymore money.

T5S60 · Post by **T5S60** » 23 Apr 2015, 15:30

Will check into these suggestions. Could you link me to the recall info for the throttle control module? I have looked around but all I can find reference too is a extended warranty to 200k miles or 10 years, which wont help me.

Post by **abscate** » 25 Apr 2015, 13:49

The warranty period for Electronic throttle body was extended to 10 years from first date of service, so that time has expired. There was no recall.

The options are cleaning, rebuilding, or a Xemodex replacement.

T5S60 · Post by **T5S60** » 26 Apr 2015, 11:42

Just replaced the spark plugs... engine seems to idle much smoother now. I measured a 50-54 gap on the old plugs and they had a little oil down there (probably spilled from the jiffy lube techs). At any rate I also saw a 5 mpg jump with the new plugs.

The engine rpm still seems to fluctuate at idle by about 50 rpm (900-950) but its much less noticeable. Not sure if I should just call it a day at that and leave things be or continue trying to figure out what is causing the minor rpm fluctuations. Will post some pics of the old plugs when I get a chance

Post by **abscate** » 05 May 2015, 01:57

T5S60 wrote:Hi, my Volvo has had a rough/hesitant idle now for a little bit and I'm kinda curious what could be causing it. Another thing I noticed is when its doing its intermittent/rough idle the dash lights actually get brighter/dim. Any Ideas what could be causing this?

I heard someone had a similar issue and he was able to fix it by replacing his mass airflow sensor. He actually diagnosed the issue by removing his MAF and running the car without it (is that safe?). I will start by seeing if I can clean the airflow sensor (with MAF specific cleaner). Any other suggestions?

Just following up on this.

Usually you disconnect the plug on the MAF and see if the car runs ok. With no MAF the Engine control system defaults to a look up table of fuel delivery based on rpm and will run pretty well, but with lower mpg. Removing the MAF is a bad idea as it would open the intake manifold to unfiltered air.

My clean MAF success rate is about 50%. Just did one on SWMBO BMW at 130k miles that worked!

Post by **precopster** » 05 May 2015, 15:09

Replace your oil cap seal. It's not spilled oil; the oil seeps slowly from under the seal and into the channels which lead into the spark plug wells.

Usually a 99c part from FCP or IPD.