My car would not start. Was told to slam into park then try. This worked twice. Now will not. Any suggestions?

get it serviced?
hard starts are usually never getting a tuneup, (like spark plugs?)
slamming in to gear is normal if RPM is too high in park, is it.
wont move , in any gear, car wont move even in reverse.
and RPM of engine does what , sticks low, like 800 rpm
or screams at the advancement of right foot.
need lots of details. we cant drive car, but if could in 5min flat all that is clear,
eg:
transmission slips
engine weak
engine racing in park too high.
wont start and misfires when it does.
is fuel fresh, not year old.
ever get a new air filter and fuel filter. if filter is outside tank.

Take it to a mechanic and have it repaired. The parts are so far out of alignment that no amount of additional slamming will solve the problem.

may be short of gearbox fluid or tick over may be to high

Start of a failing trans or just dirty valve body or solenoids,
inside the oil pan

Keep up what your doing with the slamming & it will be junk in a couple weeks

Park it & resolve any trans issues

Price the repair. Ford does have some Credit programs for car repairs and you might be surprised about the terms. Their own Credit card can be used for oil changes and tires as well as brakes and so forth.

Your problem is not only with starting but can result in the car lurching or rolling if not properly repaired.

make sure it is completely in park. sometimes you have to slam the gear shift into park position. make sure your key in in the on position. put the car in gear then slam it into park that should allow you to turn the key off completely and remove it

Slam the shifter into park and then pull out the key. If it won't come out SLAM the shifter into park again. Wiggle the key. Repeat if necessary.

Sounds like a loose battery terminal, when you slam the door it shakes the car and in turn makes the terminal connect. take off the battery terminals clean them and re attach, see if that helps.
Good luck.

Its propably the door courtesy switch. Remove it, clean the wire and contacts and try that. Hope that helps

Do you have a check engine light or is the engine idling real fast.