Car runs better after 2nd start
 

It’s weird and I don’t exactly know how to describe it besides when it’s cold and I let it warm up it’s a mess. Does the 3k start up fine and jumps between 1200-1000 while warming up. After it will drop to normal idle but backfires when I let off throttle it shift. On a stock ecu. But after I’m done driving and go into a store I can come out. Start the car and it drives amazing. What is even going on? Car has me stuck on a fix

check fuel pressure on start up

what happens when you cold start it in gear? That should disable the 3000rpm accelerated warm up system.