My 93 has HCI, b303. It is very cold hearted. It has to warm up before it will idle on it's own. I've got it set to around 900 rpm. It stumbles down to 500 rpm, kicks up to 2000, slowly comes back down then stumbles again, maybe a slight pop out of the intake when it does this. Takes about 10 minutes depending on how hot it is outside. I got a new TPS last week, set it to 1.10, took the cone filter off, took the breather off of the valve cover, and it runs much better once warm. So is this a IAB problem (it's already been replaced once), or do I have a lifter not pumping up? I don't want to bend a valve on my GT40X heads. Thanks!