My car has this weird problem where about 1/4 of the time you start it, it will rev to about 1500rpm then drop down to about 500rpm. And it fluctuates like this untill you throttle it out, if not it just dies usually, but sometimes it will fix itself. I've replaced the IAC but its still doing it. When i first put it in it would idle about 2000 rpm, after adjusting the idle screw it still didn't change it, So i took the IAC out and screwed the needle in more so it didn't stick out so much and that helped. But it still is idleing weird. I've changed plugs,wire,distributor,adjusted timing, no vacuum leaks that I can find. I also thought maybe I should replace the fuel filter but I mean it only does this sometimes not all the time so thats what has me stumped. Any suggestions would be appreciated, Thanks!

Come on someone has to have had a similar problem! Could it be the ECM is messed up????