as the title states, when i start my 89 Formula 5.0 TPI up after it's sat overnight, the idle hunts all around...i turn the key and it will turn over but it will stutter a little around 700 rpms and then rev all the way up to like 2000 for a few seconds...come back down to like 700, stutter a little more and rev back up to 2000. eventually i'll intervene and press the gas for a little while and it calms down and settles down around 750. after that it's totally and completely fine. car runs and idles great.

any thoughts on possible causes?

 

noone else has heard of this issue? a friend suggested it could be my air/fuel mix is not correct at start up...any thoughts on what could cause that? can't be 02 sensor because it's still in open loop...i have a new MAF sensor and TPS sensor and cleaned out the IAC.