About two weeks ago I bought a 1993 volvo 240 auto sedan w/ 88k miles, which was serviced before delivery. The other day when I went to start the car the engine block began to shake and then my car died. I was able to get it going after a couple of attempts. But ever since then my car has seemingly lost a lot of its torque. My friend suggested that it might be the gas and that I pick up some dry gas. I'm really confused as to what the problem is. Fortunately it's still under warranty but I have to wait a couple of days before it can be looked at. Hopefully it's a simple problem. Any help would be appreciated.