I have a 2001 s60 with 136K. It's been great and is still getting 31mph with a combination of city and highway driving. I dive a lot 50miles to work each day.

Lately I notice when I start the car up it idles funny. It's almost like someone is pressing on the accelerator intermittently. It will fluctuate above and below 1K +/- 400K.

Any suggestions?

Time to check the spark plugs, check the coilovers for cracks, and start looking for vacuum leaks.

If it only happens when cold, your fuel/air ratio might be too rich, so check the ECT sensor for a good 0hm reading.

Klaus
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Always willing to listen, just not able to take direction.

I'll check into when the last time the plugs, wires, distributor cap, and rotor were changed. It actually idles +/-2K between 800-1k.

Is the ECT the oxygen sensor? All my mechanic experience is on a volvo 240 so I'm a little lost when it comes to DIY projects on this car.

How do you check for vacuum leaks or do you need the pro's to tackle this one?

ECT = engine coolant temp sensor, located just below the thermostat. Follow the top radiator hose to the engine. Newer cars have the ECT and thermostat as one unit, I believe yours is still the old style and separate.

Vacuum leaks can be spotted visually. Just check any elbows for cracks, and make sure nothing is loose. There are miles of hoses, so take your time. Also check the air hose connection between the air filter and throttle body.

You have an electronic throttle which could also be going bad. The fix for that is around $500 at www.xemodex.com

Klaus
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Always willing to listen, just not able to take direction.

The website says it's pre-loaded with software. Does this mean it can be installed by the owner and not need a trip to the dealer?
Marlin

It's the throttle body. I took it off and gave it a good cleaning with brushes and throttle body cleaning. It is idling smooth now. If I'm lucky I'll get another year out of my original throttle body. I'll be replacing it with a xemodex rebuilt one once this original one expires.