GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello, my name is***** would usually scan the computer for codes first to see if it is reading any issues. Most of the time this is caused by a failure in the fuel rail pressure relief valve. These will fail and stop sealing correctly. This is by far the most common cause of this that I have seen as it allows the fuel pressure to bleed off when driving. If you need more help please let me know.