Tuning issues

[Russ85]

I have an 85 gmc with a 305. The two issues I'm having with it are, it doesn't idle well always when the ac is on and, it runs a little when you turn it off like a diesel. I was wondering if anyone can help with these?
Thanks

 

[twinturbo427]

If it still has the stock carb, or a non electronic Quadrajet replacement, it should have the a/c idle solenoid on the driver's side. Check for operation, and it can be adjusted by turning the rod/nut that touches the linkage.

 

[CSFJ]

For the run on after shut-off, check your timing.

 

[Russ85]

Thank you