Why do I only have heat when the car is driving

SOURCE: gas smell coming from vents when heat is turned in 2001 pt cruise

hmmm shaking may be a tune up issue and as far as the gas smell goes i would take it to the dealersdhip and have them diagnose it

SOURCE: ENGINE LIGHT ON WHEN DRIVING

I had a similar problem, The dealer said it was the O2 sensor.

SOURCE: water entering via rear heat vent

looks like if its not antifreeze u might need your windshield sealed or if its antifreeze u need a heater core

SOURCE: when driving the steering wheel

It's stalling on you. Like you just switch the car off.
A bad cam position sensor or crank position sensor can cause that without registering a computer code.have them checked

SOURCE: cannot remove key from ignition,

Try this....I know it sounds silly, but I had an old galaxy that did this same thing....

After you put the car in park, (I am guessing it is on the steering column), do NOT let the shifter go into it's "parked" position, but rather, leaving it in park, pull the shift lever toward you, but do NOT move it out of park. Kind of like you have to do when you are going to pull the shifter out of park, and into another gear, ya know? While holding the shifter in that position, NOW try to remove the keys. Did this work?

It is a Safety Switch, that some vehicles have. However, if the shifter never had the problem before, and suddenly, it is doing this, you may have a small broken part inside the steering column, that will not allow the ignition and steering components to LOCK.

Good Luck