1976 hard time idling after AC and heater removal

[dpuma8]

My Z was running pretty well  before breaking off a bolt in the thermostat housing. While waiting for replacement parts to come in, I removed all AC components, heater, dash, and I added a three row radiator.  After getting the thermostat housing back on, the car had a hard time starting and when it did, it barely idled.  It sounded like a huge vacuum leak was somewhere on the driver side of the engine.  I used starter fluid and sprayed everywhere and there were no signs of vacuum leaks even though I could hear them.  When spraying looking for leaks, the fluid would sizzle between the 3 and 4 cylinders near the intake manifold.

 

Next what I did was open the idle screw which made the car idle correctly and start up fine but the problem was when giving it gas, it would stumble a bit.  On test drives, it sounded fine but then coming to a stop sign meant the car would barely idle again.  Last night I drove around the block and at a stop the engine would die if I gave it any gas at all.  This morning it wouldn't start at all so I don't know where to start.

 

Any suggestions?

[NewZed]

By "idle screw" do you mean the idle air screw, or the idle speed screw?  If you added more AFM bypass air that would lean out the mixture.  If you just added speed, that won't affect the mixture much.

 

Not clear how warm the engine gets while you're testing.  Could be that you switched the coolant sensor plug with the thermotime switch plug.  Or the coolant sensor has lost connection.  Maybe it's really just very rich, and there is no vacuum leak.  Pull one of the small hoses from the intake manifold and see if idle speed goes up or down.  If it's already lean from a leak it would probably go down, if it's rich it will probably go up.