Rough idle and poor start ups in cold weather what

Have you had car diagnostic tested?
Live data from cold could show a poor coolant temp sender or wiring.
Get it tested...save money on not guessing.
Roger

Leaking intake manifold (vacuum )

The flashing and rough running is to to a misfire or misfires cause by arcing due to moisture on ignition components. Eventually these misfires can lead to other problems such as damage catalytic converter. Start by identifying which cylinder(s) is/are misfiring. The arching can be reproduced with a spray bottle filled with soapy water. Spray the ignition components (wires, coils, distributor cap...)and look for the vehicle to idle rough. Replace any faulty component.

choke control coolant temp sensor intake temp sensor air temp sensor. ck all of this

The idle valve is the most common problem for hard starting in cold weather. I would recommend having it removed and inspected for contamination. Sometimes they can be cleaned out. If it has heavy carbon buildup, you may have to replace it. (if the idle valve is removed, the shutter inside should easily move when you rotate it from side to side and you can also look at it with a flashlight for a visual inspection.

base gasket on throttle body is probaly leaking with engine idling spray alittle starting fluid on base if it idles up or dies out that is base gasket

Usually @ 50-60,000. New air filter, Gas filter, Plugs and wires.......If car starts running rough or hard to start and miss fire is a good sign of a tune up needed..............Hope this helps.

change the air charge sensor on the back of the intake

Sounds like a cold start valve (which is actually an additional injector in the intake to assist in cold starting) If you can get it to your local prts store while the light is on they will read the codes for free and tell you what the car thinks is amiss.

The correct spark plugs are very important. Glad to hear you got it fixed good.