Home › Forums › Stay Dirty Lounge › Service and Repair Questions Answered Here › 04 gmc envoy 5.3l › Reply To: 04 gmc envoy 5.3l October 13, 2020 at 8:30 am #986690 Jeff MooreParticipant If it’s reading to high at idle could this be the cause of high stft readings making it go lean because the ltft never moves from 25%. The owner tried one before but that’s before I cleaned out the clogged up exhaust and blown intake gaskets.