Friday my car is driving fine. or at least as good as can be expected. well I park it friday night, and don't go nowhere for saturday and sunday. Get bac in on Monday and I notice it feels a little weak. While in traffic on my way to class she starts knocking but not bad. On the way back home I put some 91 octane in to try to help it. It got a little better but then got worse a lot quicker on the way home it starts knock really hard and just seized up and completly died. Now when I try to start it, it's knocking so hard it sounds like a diesel truck and won't stay running without me on the gas. What happened? I'm not sure what the problem is. fuel, timing what do you guys think??? HELP