stilmon

hey guys i just bought a 1998 transam, ok it has a corvette motor replacement (out of vette) MOTOR HAS 15000 MILES CAR has 74000 miles i noticed it has a hard time starting sometimes but when it does start idles very good now when i get on it it seems like it heisitats i know motor is fine but it does have about 8 codes being tripped like knocksensor low circuit airtemp lo circuit ect. now all the sensors are from the original ls1 that was in it the motor now once gain is the 01 vette ls1 so do u think its the codes? maybe it needs the vetts eu? maybe i wasted my $3000? please help thanks guys!!!