Ok, My check engine light has been comming on. I changed the EGR valve and sensor and it came back on. BTW, I have a 99 Miata. I was told it could be a loose gas cap. How do you know it's tight enough? Is it tight when you start getting clicks or do you have to turn it several times when you start getting the clicks. I want to rule out a loose gas cap.

Thanks

 

Turn until it clicks. Depending on what CEL you're getting that should tell you if it's the gas cap or not. I can't remember the code, but the 3 has a different code for a loose gas cap.