weird surging issue
 

Hey y'all well I broke down and bought 2 new batteries and the truck runs great now starts great etc with the exception of this weird surging issue, I start it up and it runs fine and as it gets close to operating temp its surges or pulsates (rpms go up and down) but once it reaches operating temp it stops and runs perfect there is no smoke or codes or anything and idk why it does this I'm at a loss, anyone have any idea? Its a 97 k3500 6.5

AC Delco coolant sensor?

Flight systems PMD about 2 1/2 years old?

TDCO ever been properly learned and do you know the setting?

Timming stepper motor secure and in proper working order(time set command to test with scan tool).

Racer55 I don't know any of that I bought it used and its had problems since day one, I've replaced the lift pump injectors relocated pmd and new batteries the truck runs amazing now with the exception of this issue, some friends keep telling me it has something to do with a temp sensor but idk

Ok well they are few things to get checked out.