My car die at stop lights. Can the cause be due to a cracked PCV tube.

To check the PCV valve, temporarily remove it. If there is a lot of pressure and air flow coming through the hose it attaches to, compression that is suppose to remain above the piston is getting into the crank case. This may be due to a cracked or worn piston rings or rings, a cracked head or engine block, or a hole or crack at the top of a piston. If there isn't much pressure or flow at the hose attached to the PCV valve, the valve is likely stuck shut. If you hold it next to your ear and shake it longitudinally, you should hear the valve clicking back and fourth. This indicates it's likely fine. If you do a compression check of each cylinder and find 2 cylinders that are next to each other both low on compression, a blown head gasket is a likely cause. All engines will have some amount of air flow through the PCV valve.

The PCV allows one way flow and vents pressure (gases) from the engine and sends them to the intake side of the air breather for re-introduction into the air intake system of the engine.
A non-working or stopped up PCV can cause a build up of pressure, which must vent somewhere. The oil dip stick is often the choice, especially if there is not a tight seal at the top of the tube.
White smoke or steam/ vapor usually means water is entering the internal workings of the engine. Head gasket leaks, cracked heads, and cracked blocks are the common source of such entry. Also water leaking into a cylinder will cause hard or poor starting as the piston is working against the volume displacement of the water. Upon cranking any water so leaking will be exited through the exhaust system and leave the vehicle as a white vapor out of the tailpipe.
Considering that most diesel engines have some "blow by", some water may be expelled out the PCV circuit.

Problem Description and Possible Solution
A vacuum leak from the PCV grommet. A vacuum leak can cause the Check Engine Light to illuminate. The molded rubber hose connections may crack and collapse, causing the vehicle to run roughly. A damaged PCV hose will require replacement.

Problem Data
Average mileage: 137,860 (98,300–203,000)
17 model years affected: 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007

It is kinda rare but look at the mass air flow tube . Make sure that its not cracked , dry rotted or loose. When you put it in gear the engine/transmission mounts will allow a little too much movement due to old or bad mounts. This excessive movement causes the tube to crack.
Next time you start the vehicle have the hood up and while its idleing move the flex tube around . If it idles up/down or dies the tube is cracked. Good luck

ford focus are well known for the pcv tube going to intake manifold get soft and collaspe and well soon crack and log a check engine lite for bank one lean, due to vacuum leak, pcv valve is driver side front corner of the engine block just below the head.

I just had the same thing. Engine light came on. Rough idle. Codes P0171, P0174, P2195, P2197. Within a week the idle got so bad it would die at stop lights. Seemed like a vacuum leak affecting the idle. Found it today. The elbow where the PCV tube enters the vacuum port on the upper intake was degraded, collapsed and had a whole in it. Wondered why it degraded. I disconnected the tube from the PCV valve and found it quite oily. I think the oil sat in the elbow at the intake because it is flat on top of the engine and could pool there, causing the rubber to degrad. Found a preformed piece of coolant hose at O'Reilly that was the right diameter and cut it to length. Put it on, runs like a charm. I ordered a new PCV valve because I think too much oil was coming through it and caused the hose failure.

Look at center of engine, at back, and you'll see a black tube coming from drivers side rocker cover, to a short black piece of rubber hose like a 90 degree elbow (which usually cracks or collapses and causes problems).
That should attach to your PCV valve.

It will be on the valve cover, usually a rubber tube will lead from the PCV to the intake. Be sure to check the tube for cracks. If the tube feels spongy, change it also. This is caused by the heat which makes the tube collapse and can cause idling problems and along with other issues.

Look for a hole or leak in your air intake tube first, then do a basic tune up...plugs/rotor/air filter/dizzy cap (if needed) and inspect vacuum lines for cracks......these would be the most common causes of your problem

Could be either the ignition coil or an injector problem whereby the latter could be caused by impending failure of the on-board computer.
Check with any chain parts store in your area by phone and ask if they offer a free code check for your car.
Even without a check engine light, you may have a code (or more) stored in the ECU.