frequently, it fails to start the engine immediately.

Hello, I understand the situation, but I'd like a little clarification. I need to know how often this occurs, what you hear, see or feel when starting the vehicle successfully and unsuccessfully, and any other information you can pass along. What do the lights on the dashboard do while you are trying to start the engine? You should see them all turn off until the key rotates from "start" back to "run/on". Is there a check engine light while driving? I assume not, but if there is, let me know what trouble codes you find with a scanner.