Was doing the AutoVE on a 2002 5.7 6 Speed, everything was going perfect and all of a sudden it went Extremely Rich. Pulled over, shut the motor off, did a free-air calibration on wideband(Innovative LM-2) turned the motor back on and motor has a real bad missfire, motor shake's, stumble's between shift's.....Wideband is showing rich AFR(12-13.2)....Before incident AFR was 14.5 in all part throttle areas, under 4000RPM, & Ben's were .99-1.01 .......I'm going to do a compression test today but hopefully it's something minor..... Any ideas on what might have happened?
Stuck open injector?
Bad coil?
Everything was going perfect...