Hi everyone. New here, but this seems like a very good community of enthusiasts. I have a question I need guidance in. I have a 1992 full-size Blazer with a 385 stroker. Now I am working on tuning it and am headed in the right direction I believe. The truck is idling relatively well when in park. The problem is when I am sitting at a stop light with the truck in drive, in a short time the truck will begin to idle hunt. It gets so bad it will actually make the truck rock and lurch forward. I can't remember off the top but if I had to guess I would say it is jumping 300 or so rpms when it does this. Does anyone have any thoughts to this or where to begin looking? Thank you.

Had a bit of the same issue and it came down to having to make the iac relearn itself.

Wife'sCar,

Thank you for the reply. I am new to the tho setup, would you describe how this is done? Thank you.

Here's what I did.

have you checked for vac leaks? worn throttle shafts? cleaned IAC? You won't be able to tune around mechanical issues...