I have a 2000 Volvo S40 1.9lL Turbo Automatic and it shakes quite a bit when im at idle regardless of what gear i am in. I have noticed that it idles at about 500 rpms which seems kinda low cause it doesnt go by itself when i take my foot off the brake while im in gear. It also seems to accelerate pretty slow for being a turbo model and it also seems kind of rough when im accelerating. I am thinking that it might be either the spark plugs or the fuel filter. There is no check engine light. I have been putting the lowest octane gas in it(i think 87) but i just figured out thats its turboed..and im gonna switch to the higher octane fuel. Could this contribute to the problem?

There are several reasons the car could be shaking. A component in the engine could be off balance, There could be an issue with the valves not sealing properly, reducing compression. It could also be the engine mounts. There are many other problems that could cause this. If you think you have any of these problems you need to have it serviced asap, as these could cause a bigger and more expensive problem.

Sounds like a motor mount. I have an 07 Escape that needs one. I also drove a 2000 Saturn that needed one so bad it shook the whole time you drove it. Get this fixed as soon as you can. This can eventually get so bad that the engine could fall out from under your car.

Hello

Get it checked as it could be something like the engine mount rubbers

Andy C

I can think of about 70 different reasons, here's one: one of the valves on one of the pots isn't closing well