2000 red gt

i own a 2000 mustang gt. i bought it over a year ago and the whole time ive had it ive had a problem with its idle. if i turn the ac or heat on at all its starts acting weird and idling very rough, and sometimes after a while of idling rough ill put it in neutral and it will die, while im driving. ive tried just about everything and nothing has fixed it, new coils and plugs, new o2 sensors, new iac valve. if anyone has anything else they would recommend id appreciate it. im lost.

Z28KLR

That's a healthy list of parts you've thrown at it. Dumb question perhaps, but is the check engine light on?

FWIW, I was gonna guess IAC. How about vacuum leak or other unmetered air, is that possible? Does giving it throttle keep it running?

99GTvert

Have you replaced either air or fuel filter? Is the service engine soon light on?

kast1376