Why won't my car stay running unless I hold my hand over the air intake

Hello Electrified, Since placing your hand over the intake allows it to run in cold weather you have to consider the higher air density. Since there is so much more oxygen in the air the engine is sucking in, a small vacuum leak or intake leak will be much more pronounced than in warm weather. Placing your hand over the intake should force a stalled engine, since it doesn't it is getting air from somewhere else. Cover the intake and listen for where air is entering the engine. Throttle body gasket, idle air control valve, intake manifold, valve cover, oil cap, etc. Basically anything that is subject to vacuum could be leaking. It must be a considerably large leak so you'll hear it. Check engine light? OBD trouble codes?

How are you holding your hand over the air intake? ..That big rubber air tube MUST be in place and secured with NO leaks before the engine will run! .. Does it have one of those 'gadgets' called a cold air intake on it? .. Mass Air Flow sensor still properly connected?