Hi everyone,

I own a 2000 S80 T6 with 93K miles on it. I am the original owner. The car has been great. I noticed two problems wich I originally thought were unrelated but now think are related. One was that the car would stall out while I was driving it. It would always happen as my foot was off the gas and the car was either coasting or decelerating. FOr instance, turning onto a side street or in heavy stop and go traffic on the highway. This happened maybe once every two months or so and has been happening for the last year and a half.

I also noticed while driving at night on back roads that my headlights would dim slightly and I could feel the power steering loose just a little bit of power assist at the same time. This also only happened when my foot was off the gas and while I was coasting. I recently concluded that the car was "almost stalling" and certain power consuming devices were being starved of power, namely the headlights and the power steering. Now when I drive at night and I take my foot off the gas, the headlights always dim a little bit before brightening back up.

I'm not really interested in having the dealer spend alot of time investigating what is wrong $$$. I told them about it and they said they couldn't find anything wrong with the car.

I recently tried using a fuel injection system cleaner and I also try to use a higher grade of octane gas when refueling.

Does anyone have any ideas as to what might be causing the problem?

Thanks.

I would clean the throttle body really good.When carbon builds up on the throttle body it plays games with the computer system.Dropping the idle when the idle is lower than normal that will cause the alternator either to not charge or charge very little causing the lights to dim.So I would try that first and see what happens from there.

Thanks for your reply. I will try that. Couple of questions. How do I identify the throttle body? I googled the term but could not come up with a picture or description of where it is. And what would I clean in with? Can you give me a general idea of the procedure? Thanks.

Ok when you open the hood look down and find the cooling fan.Look on the engine just infront of the fan.Look for a rectangle aliminum box type thing.It should have a yellow or white sticker on it.That is the throttle body.Also you can follow the black pipe that goes from next to the radiator to the engine it goes to the throttle body.It will be kind of a pain to get to it and remove it.You will need to buy a gasket for it before you remove it.

ok I'm Having the same problem, My s80 volvo 1999 has 90 now and has been running ok I think. But now wen I'am driving or the car is on stop I see the my headlights are dim and also thein side ligth of the car the did you think I may have the same problems?

also when the car is on full stop it looks like if is going to stall and at the same time my interiar ligth and Headlights will dim too.


Any ideas.

thank you for any infromation.

ORIGINAL: ajo

ok I'm Having the same problem, My s80 volvo 1999 has 90 now and has been running ok I think. But now wen I'am driving or the car is on stop I see the my headlights are dim and also thein side ligth of the car the did you think I may have the same problems?

also when the car is on full stop it looks like if is going to stall and at the same time my interiar ligth and Headlights will dim too.


Any ideas.

thank you for any infromation.



Yes I believe you may have the same problem.

Quick update. I had the dealer clean the throttle body and PVC today. Approx. $280 dollar tab. Side note: They say I may need a Mass Airflow Sensor in the future.

The car runs much better and it did not seem to want to stall out on the way home (thank goodness). I was going to try to clean it myself but it looked a little difficut with the turbo unit etc...

Also, the service manager said the turbo fans looked almost like new. I guess I'll have to address that problem over the next few months. :-)

Thanks for the advice.

Im glad it is running better.If the pcv was clogged it will throw a mass flow sensor code in the computer.I would not worry about it till it starts acting up again.

I have a 2000 S80 2.9 with 92K on the odometer and make be experiencing the same problem, only my car does not stall out. I've noticed that at idle it will surge about 200 rpm and the headlights and interior lights will dim slightly. Do you think cleaning the throttle assembly will correct this or could this be due to a loose belt or something?

Well the accessory belt runs the alternator which will charge the battery. I'm pretty sure the electronics all run RIGHT off the battery so it probably isnt a belt problem. If it was then youd probably just keep losing power until the battery ran out. I'd check the throttle body.

Start with cleaning the throttle body and see if it helps.

ya that mass flow air sensor, its quite expensive, luckily they did my mass air flow sensor under 100% good will, when i asked how much they would have charged me they said about 500-600$...

I have a similar problem with my s80 2001. I have trouble accelerating smoothly from astop. And I have the similar problem with stalling at slow speeds or near stop then acceration. I don't have any surge problems. I was hoping it would be a software upgrade, but I'm not sure.