I made some changes last night on the Lower VE Table trying to reach the magical 128. I also made changes to the Upper VE table. After taking it for a drive, I see a lot of 0s in spots for the Oxygen sensor reading. Does this mean the car went that lean now? Overall, the O2 sensor seems to be working because I see a range from 0 to 750. This appears at different RPMs also. I love this stuff. Any help would be appreciated. BranZ

 

What computer comes in this blazer? Also, how hard is it to tune on the computer. Also, it is the vortec 4.3. Thanks, BranZ

 

The ecm tries to AVERAGE an AFR of 14.7. It deliberately goes rich and lean to keep the converter happy. there's a huge difference between maintianing 14.7, and averaging 14.7. the lean to rich readings are totally normal.