Im having a problem starting my car, ive checked everything that i can think of to make it start. I have taken the air intake off to make sure it has enough air, ive sprayed starter fluid into the engine, ive gotten a jump from another car, ive even checked the timing belt and adjusted it multiple times to make sure its correct, and ive also taken a spark plug out to make sure it has spark, and it does. So what am i missing? What else is there to check?