Ok I just recently picked up a 91Z w/ 350. It runs great and is damn fast for being bone stock. Anyways, when I'm sitting at a light in drive the idle has like a miss to it and sometimes it stalls. Here's what I've done so far. Tune-up, new EGR, cleaned IAC, AFPR set at 48 PSI(by the way still had the idle prob w/ the stock FPR), etc. Can anyone think of anything else? No check engine light.

 

my idle at a light was pretty rough there for a while too. than one day my alternator wasnt charging what it shoulf of been so i replaced it and now my idle is 100%

 

did you adjust / mess around with the iac and tps at all?

https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

 

yeh i would check the tps.