I am having an annoying issue with my cat. Once every 10 times or so, I get in the car and it will crank but not start. I walk away 5-15 minutes come back turn the key and she fire's right up. If I stay in the car and try all the reset options for the immobilizer such as turn key on, wait, then turn off, and repeat or lock and unlock manually, or wait till all lights except the 4 are on normally to star, it won't work. Only if I w walk away, wait and then try to start again will it work. Pretty perplexing! Any thoughts?

 

Check battery volts.

Check what PATS light does when it won't start.

Then use OBD live data & look for any wrong sensor (ECT, IAT, ...).

Maybe a failing fuel pump.