Bad connections, wrong readings. (need something that can read the data stream for that though.)

 

I had auto zone run a code reader an nothing came up, or would I have to connect direct to the PCM?

 

All that means is the PCM doesn't think there is a problem. That does NOT necessarily imply that there isn't one.

Need to be able to read data. And see what the sensors are telling the PCM at cold start. Most code readers will also read data...... just having one at the right time is the tough part.

 

Can I replace the PCM, stupid question? Ha I'm learning as the problems develop with this truck.

 

The check engine light only comes on if there is a problem effecting emissions. Most parts stores only use cheap generic code readers and if there's no cel, their reader won't show anything.

 

PCM is probably fine. You got something else going on there.

 

It wouldn't hurt, and has no cost.

 

you might just have some garbage gas. I started using mid-grade since this happened. This morning in Mid-michigan it was -3 degrees and my truck strated right up.