Hello everyone, thank you for allowing me to join your forum. I have a 2000 Chevrolet Blazer with a 4.3L Vortec and I am having idle problems, it started just when the heat was on mostly the defroster, then it was happening when any HVAC controls were activated, and now it is anytime. The idle varies anywhere form 600 (which is normal right?) to about 1000 to 1200 rpm. This problem only seems to be periodic but it is a problem. I do appreciate any information on this problem, and thank you once again for letting me become a member.