Car idles fine, but wants to die when I release the throttle
95 LT1 Z28 automatic convertible. Bone stock, no tune.
Did a head gasket job on this car. When I got it all back together, it idled really high. I replaced the TPS and IAC with new units from Rock Auto. Turned out I forgot to tighten the throttle body bolts all the way, so it was sucking in air. This problem started immediately after tightening those up.
Car started out only wanting to idle at 500 rpm. Considering how long it sat, I figured the computer needed to relearn everything. So I drove it around a bit. Every time I'd lift off the throttle completely, it would drop to below 500 rpms and almost die. A few times, it actually did die. I could hit the key and it'd start right back up. Car runs good otherwise.
My vents for the climate controls won't blow out the front no matter the setting, which I've discovered can be a vacuum problem. Is it possible that a vacuum leak is causing both of these issues? Like when I find the leak for the climate controls, could that fix my idle issue? If not, what other problems cause the stalling when throttle lifted?