Ok, so my neon wasn't starting and it shot out two codes. I had no spark so i replaced the two codes, The camshaft position sensor and crankshaft position sensor. I then tried to start the car with both codes cleared. I tried and it made a popping noise and wouldn't start, and it shot out the crankshaft positioning code again. So what's wrong? Is it the valve timing? If so how do I fix it and what would have caused the pop noice? Hopefully nothing broke. Thanks