help truck threw 3 codes last night!

[05DMAX1520]

Last night i installed my egr blocker plate and the night before that i did the shim mod and after i got it all back together i went see if i noticed any difference and i did the truck never shut down put i threw a P0700, P0746,
P0087. can someone tell me what these codes are, what caused them and what do i need to do to fix them. help and imput much appreciated!!!!!!

 

[05DMAX1520]

i forgot to mention that when it threw the codes it locked the trans in 4 gear. i could put it in p,r,n but when in drive it would only go into 4 gear??????

 

[Turbo Buick 6]

P0700
Transmission Control Module
P0746
Clutch Pressure Control (PC) Solenoid 1 - Stuck Off
P0087
Fuel Rail Pressure (FRP) Too Low

 

[Turbo Buick 6]

Maybe start a new thread in the trans forum for the P0700 and P0746