04 mercury montery trans wont go in R from drive and is spuratic in low gear when u put it in drive WHY??

It will go in reverse from Park but not from drive and sometimes when you take off from drive its like you have the brake on,.. but not always is this some sensor or the module on the tranny ? also when you put it in nuetral the rpms go up to about 2200 rpms? sometimes it works fine but still wont go in reverse from drive. i have replaced the high speed input or out put sensor and the lowspeed input and output sensor and i also replaced cam sensor. before i did all of these it wouldn't hardly run (real spuratic as far as rpms) Now it runs fine on the highway.. Please help Thanks Todd
04 mercury montery trans wont go in R from drive and is spuratic in low gear when u put it in drive WHY??
take the vehicle to a repair shop and have them look at the electrical connectors and make sure that they are tight and that you don't have what they call a terminal pin push out causing this intermittent problem. there are too many things that could be causing your problem to mention.