95 G30 5.7 w/160° therm 4L80 20 ft motor home.
Problem started soon after purchase, previous owner stated "nothing like that ever".
AC compressor clutch came apart 60mi on first voyage. Unplugged ac clutch then 20 mi or so went into limp mode, hi idle, trans limited to either 2nd or 3rd gear. Made it home replaced idle air along w/ac compressor, everything else checked out tpi, ecm temp sensor, etc. no codes no vac leaks, then O2 sensor didn't seem right so I replaced it(Bosch). Seemed to do the trick, drove locally several times, okay. 2nd voyage, apx 150mi limp mode. Various codes every 150-200 mi reset. Most common was analog digital error. While in Alabama talked to a guy that seemed to know and convinced me to change ecm temp sensor and ecm. On my return, same stuff every 200mi. I did get PROM error a few times along w/analog digital error. Another pro said O2 sensor needs GM part & junk the Bosch. Picked up a PROM but haven't tried it yet. Today O2 sensor circuit code and 85.
Problem started soon after purchase, previous owner stated "nothing like that ever".
AC compressor clutch came apart 60mi on first voyage. Unplugged ac clutch then 20 mi or so went into limp mode, hi idle, trans limited to either 2nd or 3rd gear. Made it home replaced idle air along w/ac compressor, everything else checked out tpi, ecm temp sensor, etc. no codes no vac leaks, then O2 sensor didn't seem right so I replaced it(Bosch). Seemed to do the trick, drove locally several times, okay. 2nd voyage, apx 150mi limp mode. Various codes every 150-200 mi reset. Most common was analog digital error. While in Alabama talked to a guy that seemed to know and convinced me to change ecm temp sensor and ecm. On my return, same stuff every 200mi. I did get PROM error a few times along w/analog digital error. Another pro said O2 sensor needs GM part & junk the Bosch. Picked up a PROM but haven't tried it yet. Today O2 sensor circuit code and 85.
Jun 28, 2026 at 3:27 AM
