When my 2000 volvo s40 is at a stand still it idles rough, what could it be?

You may want to change the idle control valve

I had a similar experience. Finally the car started overheating. Turned out the thermostat went bad and the radiator blew a leak. Had those replaced. Runs great.

the tube for the turbo is shot. as for the rest.... get rid of car

yes it sounds like eithor you have a vacuum leak or your idle air control motor is out or going out test the iac motor too see if that the problem with a small jumper cable hope this helps

goodday! I asked a question about my S40 Volvo 2001 high idle. The answer is great, but I did not use it because I found out that it the car was giving another fault.

there are times when the engine woulld crank for a long time without firirng. when it finally does it would be powerless to an extent that it doesn't respond to the gas padel. its like it activates some form of inhibitor. When it behaves like that the only way to eventually start it is to disconnect the battery and wait for a few seconds. Now I wonder if it is still the idle motor

If your airflow sensor (meter) is faulty then nothing in the fuel system will work as it should. This sensor tells the computer how much air is entering the engine so it can determine the fuel needed. It sets the amount of fuel by adjusting the length of time fuel is injected. So obviously your problem.

This seems similar to a Volvo C70 which i have worked on......the fault was the Mass Air Flow Meter was faulty........does it do this in all the gears?

Its called torque-steer. serach this phrase and your question will be answered.

clanging on rough roads\
Ck exhaust pipe securements and clearances from body. huge o rings are used to suspend exhast and sometimes break and fall off.. Good luck
vibrabration on uphill acceleration
chk motor mounts by holding brake and accelerating
Sway bars seldldom are a problem unless mounting bushings are worn resal bad

check your mass meter and air filter