since replacing the front fuel pump and o2 sensor, and ajusting the screw on the throttel body to raise the RPMs. the truck now stays running. The engine does not stall in drive but it does stutter almost like its going to stall and its worse when shifted in reverse espically when the engine get warm. When driving the transmission shifts hard going from 1st to 2nd gear and stutters in 3rd going to 4th gear and wont willingly change gears so I have to step on the gas to increase the speed before it will shift properly. I did a full tune up and change the transmission fluid and filter cleaned the throttle body and IAC. Also checked the codes and came up with 621-629- with the engine off and 538-536-632- with the engine running... I just cant figure it out

 

Since both of them codes come back to soleniod body failure, I would look at that first. Bad, thing is that you cant find out if its bad unless you just replace it and see if it is fixed, and they are 100-115 dollars. Good thing is I thought I had a spare one around my house somewhere, if I can find it i will send it to you for cheap. But that is just what the codes are pointing towards. Don't know much more then that.

 

still cant figure this one out, could it be a fuel pressure regulator?