[steveo3318]

First thing is check for vacuum leaks. Mine done this and it was because I left the brake booster line off. If the truck is idling was to high then coming down slow try the last two parameters. Fitech generally sets these up for automatics.

Here's how to set your idle correctly. On the main screen that displays all parameters go down until you see IAC STEPS. with the truck fully warm you want to see this number between 5 and 10. This is directly affected by the idle screw. Very small turns makes big changes on this end it can be done while running. Once it's set let it idle a few minutes and watch it. Kill it for 30 seconds and restart. Watch it. It's learning. Adjust your idle screw and keep checking IAC STEPS until you are between 5-10. Make sure NO VACUUM ADVANCE IS HOOKED UP WHAT SO EVER. Are you using the unit to control your timing? If not make sure that's set to TACH. This will cause it to float. Make sure your fan 1 is turned off if not using a fan. Try this and report back. Your going through an extremely similar case I had. Just stay calm and it can be tuned out!