Does not matter whether on a cold or warm engine, it takes two tries to start the engine. What could be causing this? If the spark is missing, it should not start at all. Am I correct to assume this is fuel related? 2001 Suburban with 150k miles and original fuel pump. I am not familiar with my 2001 Suburban so I have a few questions. 1 Does the fuel pump have a check valve that could be bleeding and causing loss of fuel pressure? 2. Is my fuel pump getting weak? 3. What tools do I need to check the fuel system? 4. Where is the fuel pump? 5. Is the fuel pump easy to replace? 6. I plan to keep and maintain it for a long time. What is a good service manual? Thanks.