When you put the car in reverse it moves a little, then when you step on the gas it does not move at all unless i put it in nutral or park and then reverse again

The question is a little vague but I think I know what your referring to. All modern automatic transmissions have torque converters. This is the device that connects the engine to the transmission. All vehicle manufacturers like the trans to be nice and smooth shifting. That's great but it does come with some minor drawbacks. If you are facing slightly down hill and you put your car in reverse but do not step on the gas slightly I can guarantee that you will indeed roll forward. You can eliminate that issue by holding your left foot on the brake while you shift into reverse. Then, as soon as you feel the trans engage, gently depress the gas pedal with your right foot and it will eliminate that forward roll problem.

first check fluid is full by starting the engine have it blocked put in in nutral( to fill the bell houseing ) then check fluid level, more than likely you need to add fluid exspecally if your checking it in park with engine on or off park gives you a false reading on the dip stick

Are you refer to put it in reverse then you have to rev the engine to get it to move?

It's a good chance that you have a leak and the transmission is low on fluid,check the fluid with the engine warm and running in park or nutral,if its low. Add the correct type of fluid through the trans dip stick tube.. .a little bit at a time until the level is in the normal range. If this does not solve the issue, the pump in the transmission may be going out.

Keep us updated.

The possible problem is the timimg may have jumped due to worn tiing belt i would look there first
anthoer possibility could be gas is bad and not enough octane left to sustain the extra power needed

tranny went out also check the tranny linkage

start by putting trans in nutral (with e brake on) than turn the key just short of turning on the ing press the brake andyou will need to grabe the shifter with the right hand and the key with the left hand now turn key just enough to move shifter slightly out of nutral right between nutral and drive it might a couple of trys but you will get it.

Would need more info on the heat/ac problem. But on the shifting problem check under the hood and make sure when the shifter is moved the linkage moves. If not the shift cable is most likely the problem, but check at the shifter to make sure.

They locking nut has come loose on the shift control arm on the side of the transmission, you need to put it in park and adjust it so the arm is all the way forward and the shift lever is all the way into the Park position, this should get rid of the car moving when the shifter lever is not in reverse.

Have some one move the shift lever and you watch the linkage under the car to see if the lever is moving on the transmission. Sounds like the linkage is lose. Tighten the bolt on the linkage and you will off and running again.

Sometimes it may just be the fluid level, if you have drive , drive it around the block a few times, then park it on level ground and hold the brake and go through all the gears slowley, two times. put it in park, open the hood and check the fluid level, the dip stick in the back by the fire wall, take it out and clean it, read the stick. SOME need to be checked in Nutral, if this is the case do so but be carefull that the truck has stopped moving when put in nutral!!! if it is low only put in the right fluid, and a little at a time, while it is still running DO NOT OVER FILL !!!!!!!! Also sometimes it is a SENSOR problem, and in most cases not to hard or costly to replace.