Hi everyone!

My 2004 XC70 has 139K and has always had regular maintenance. It recently started surging at idle, and dies occasionally. If the engine is revved above idle, it runs smoothly with normal power. There are no error codes.

When first started it idles normally for 10-15 seconds, then almost dies, then rpms rev to 1000-1500, then almost dies again. This repeats 3-5 times, then it runs ok.

At any time during the surging/dying, I can rev the rpm and everything is ok until it returns to idle.

Anytime the car is idling, the surging/dying can return randomly. The only time it's consistent is when the car is started, and those 3-5 times happen.

It had a new Volvo fuel pump, all filters, timing belt, tensioners, belts, oil, trans flush, etc in the last 10k miles. I've checked for vacuum leaks and all good with strong vacuum. All electrical connections are good.

Does anyone have any ideas?

Thanks much!

 

Have you cleaned the ETM on both sides. I usually pull the intake every 100k, and clean it good, (the head side of the intake will build-up some carbon deposits that will restrict airflow), and at the same time I clean the ETM on both sides of the butterfly. If the ETM isn't clean the metered air flow won't be consistent which will cause the ETM to not be able to maintain a smooth idle at lower rpm(s).

 

Fataqui, thanks. That's on my to do list.

The surging got worst and threw the codes P2188 and P2177, bank 1. I cleaned the MAF and installed new spark plugs, and it's doing better now. There's only occasional slight fluctuation in idle speed, mostly when decelerating back to idle . I know the ETM has never been cleaned and is original to the car. I think it's overdue.

I should probably clean the PVC while I'm in there too.

 

This article may help - it's about the 850 but the xc70 also has an idle air control valve. See:

https://www.matthewsvolvosite.com/id...-cleaning.html

 

The XC70 does not have an IAC valve.

 

Problem Solved:

I cleaned the ETM and now everything is fine and 100%.

I read up on removing it and it only took me 15 minutes to get it off and started cleaning. It was fairly gunky around the butterfly and shafts. Reassembly took an hour, mainly due to aligning everything under the manifold, sight unseen.

Thanks to albertj, ES6T for ideas, and Fataqui for pointing out the ETM.

 

Good job. Clean is good... I recently did the same thing, and found it worth taking the fan off the radiator to get extra room to work. I ended up using a small mirror to line things up and to get the first bolt in. After 35 years of never using a mirror I am finding it a very useful tool this time around...