94 GEO prob

When i go somewhere (i;e store) and when i come back out and crank up my car and put it in reverse the car acts like its running out of gas and i put the gas all the wat to the floor and it barrley moves sometimes the car goes dead.

what could be wrong?

Also

When i push the breaks it makes a wired noise.. i thought it was the breaks where getting bad but the breaks was like brand new.. The noise is like a granding, crackling sound.