I know this subject has been brought up in the past(did some research), but I'm going to bring it up again anyway because I have some different details. About 8 months back my wife had picked out a nice '01 Volvo S40. Well, I didn't get to drive it until December(was in training) when I noticed when I accellerate on the highway, it seems to buck and hesitate. I found the car should be taking premium fuel and put in a full tank, and didn't drive it for a couple months after I relocate to Hawaii.

Well, the car gets here, and I notice it has the same problem. I have been driving it a lot more and notice you can't really take off fast at all without it starting to buck on you. And at idle the rpms will surge by about 500 rpm.

I've been hearing about issues with the turbo and what not, but every problem this car has had yet has been an electrical problem. Any ideas on what a quick fix might be?

 

Has the check engine light flashed when it is bucking?
I would bet it is a bad coil or spark plug.

Or it could even be bad axles.