andy9743

hey guys,
new to me 00 GT 80k on the clock (bbk intake, offroad h-pipe, cat back). i've searched and found several different ideas on what could cause this (low freon, cops, IAC, egr etc.) when i turn the blower on at all-vent, a/c or heat i get a surgeing and can feel the car dip in power from the additional load...i understand that the compressor will cycle with the a/c and the additional load is normal but i'm a little confused as to why on vent, or heat this would present? ideas on what to go after first? when i turn the blower to off, the surging is gone.

thoughts on where to start?

thanks
andy

1998Slow 'Stang

Faulty/loose ground somewere.

Repzard

Either the AC is low on refrigerant or the AC pressure switch is faulty.

AC and Defrost functions,
Cycles AC pump on when in those modes

andy9743

freon is good, i'll take a look at the ac pressure switch.

SXGT

do the RPMs shoot up when this happens? mines been doing that too but only with the AC on.

andy9743

yes they do...i'm going to mess with it tonight testing the IAC fist if not that i'll replace the AC pressure switch and let you know what worked for me.