P0751 Already replaced the shift solenoid block, i was getting a b c d codes now its just shift solenoid a. It will startup and run for a little bit with no codes then it will go into safe mode and i cant get out of 3rd gear . Hoping its just an electrical problem and not mechanical.

SOURCE: transmission problem with 2nd gear (loss of power, skips)

Go to this link.

SOURCE: 2003 Ford Focus: Pulls Codes P0751, Shift Solenoid

Sounds like you need to cover basics first. The battery cables are clean and tight? Are all the wires in the battery cable at the battery making a good connection? Sounds like a common problem and is in the service bullitins is that the ground wire attached to the battery cable end that goes to the body and then to the transmission case bolt has failed to provide a good ground and the acuators and servos and even the switches have'nt a good path to ground ( their is one but it's though other controllers and the power isn't strongly grounded. I f you were following a dianostic tree of good and bad the ground is the number one cause of your problem. Don't fix the old grounds just add new ones. and then clear codes and test it again. Oil leaks near the transmission to engine connection were found by me everytime that I was assigned to this set of problems. Ground corrected and the car was fixed.

SOURCE: E40d trans will not shift into 3rd or 4th gear, only rev. 1+2

check or replace your thottle position sensor tps that trans needs to know where the throttle is to shift if it is bad it will do as you say wont shift to third
another telltale is it will act like it goes into lockup when shifting into reverse and stall the engine

SOURCE: 2003 Ford Focus: Pulls Codes P0751, Shift Solenoid

i have hard time shifting from 1st gear to 2nd gear please help me