Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
You did not state whether or not the engine is supercharged(vin 1). Here are the specs.
364-405 kPa (53-59 psi) VIN K
334-375 kPa (48-54 psi) VIN 1
If you cannot acheive the proper pressure, the fuel pump is the most likely culprit.