Hi my name is Patrick M. and I have a 2002 pontiac grand prix se 3.1L. Now I been having problems with it. To start the Crank Position Sensor, Knock Sensor, and fuel pump had to be replace. Because I was driving the car I cut off the engine, later on got back in to start it and it wouldn't start. Before I replaced the three parts I mention earlier. So when it wouldn't start the first thing i did was replace the spark plugs and wires. It started up and ran but would cut off when stopped at red lights and the RPM gauge was jumping. The check engine light came on , so I took it up to auto zone and it had the two error codes for the Crank Position Sensor and the Knock Sensor. I had them replace and then the fuel pump wasn't sending enough gas so I had it replace. Now it's getting enough gas but it still won't start. I've Checked all the fuses in the main fuse box and the fuse box in the glove compartment. And none of them is blown. Any help or advice will be helpful if there is anything else I should check.