Okay my question is ? I just bought a 2005 s40 t5 I only had it for three weeks now I drove it four times. And now it acts like it doesn't want to pull losing power and a little shake not a bad shake .it feels like it's going to stop on me and now I won't drive it .it also has a check engine light on and it wasn't on for the first three weeks I had it but like I said I only drove it four times. The check engine light now blink on and off then comes back on and stay and after a minute or two it blink again. And I noticed when I put gas in my car the gas cap is broken do enyone know if my gas cap is the reason for my losing power. Please help .