01 duramax constant limp mode problem
 

i have an 01 duramax, recently took it to the shop in my area and ended up getting charged $770 for nothing to be fixed, then come to find out they took $770 twice out of my bank. im at a end with this truck, the issue is when driving the truck it runs fine and everything when first start up, as your running down the road and go over 2000 rpm boom, goes into limp mode, now its throwing a p0093 code, massive fuel leak, the shop before tested everythign to do with fuel and everything came out good, (little on the low side) then they changed the fuel control valve, ran better, but no fix, that was it from them, now im stuck with a truck thats basically worthless, im in need of urgent help as i think its a transmission issue but no codes tell me otherwise. thanks..