I have a 91 gt all stock. When I start the car I have about 3min of good idle. After this I get a very lugging idle if that makes since. It seems to idle from maybe 800-850 rpm then drop to maybe 650-700 rpm then back again. As soon as I hit the gas it clears up and runs very smooth and strong. The only real issue I have with this idle is it makes it hard to idle through parking lots without jerking your teeth out lol. Any ideas to clear this up would be helpful.