Questions and Answers

Volvo 460 GL Idle Problems Q. Dear Vincent, have a beautiful Volvo 460 GL 1721cc manual transmission with a little problem. When at idle the car starts to rev up to 1,200 rpm and down to 300 rpm and so on. The car runs perfect but with this problem. Mechanics told me to change the Air Flow Sensor, the temperature sensor the Throttle Position Sensor, which I did, and to check the voltage regulator, but the problem persists.

I noticed that when I unplug the Throttle Position Sensor while the engine is running the idle comes back to normal, 800 rpm, for about three days and then back with the same problem. It starts revving up and down while at idle.

The car has only done 40,000 miles, no rust and in perfect condition. To change this car means a lot to put on top which is not in my reach. Can you please solve my problem?

Thanking you in advance,
Ray

A. The only way I can solve your problem is if you brought your car to my shop and let me actually work on it. From here, the best I can do is point you in the right direction and hopefully find the problem. And since you didn't see fit to give me the year of the vehicle, all I can do is offer general advice.

The Volvo 460 is a European car that never made it to the USA. So the information I have is limited. One thing you can do is to pull the codes from the computer to see if there are any stored. I think you may find some Idle Air Control Valve (IACV) stored there.

One other thing you can do, and I have had some success repairing this kind of problem, is to give the throttle chamber and IACV a good cleaning. Dirt and varnish builds up inside the throttle chamber and IACV passages and closes them up.

Read my article Cleaning Throttle Bodies for information on how to do it.